Description of problem:
The issue claims to be fixes in 1.8.2 in upstream but I can reproduce this in both Fedora and rhel:
https://github.com/flatpak/flatpak/pull/3854

Version-Release number of selected component (if applicable):
flatpak-1.8.2-1.el8.x86_64

How reproducible:
always

Steps to Reproduce:
1.flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
2.flatpak -y install flathub org.gnome.Eolie
3.$ flatpak remote-info --log flathub org.gnome.Eolie
      

Actual results:
  ID: org.gnome.Eolie
       Ref: app/org.gnome.Eolie/x86_64/stable
      Arch: x86_64
    Branch: stable
Collection: org.flathub.Stable
  Download: 12.9 MB
 Installed: 37.9 MB
   Runtime: org.gnome.Platform/x86_64/3.34
       Sdk: org.gnome.Sdk/x86_64/3.34


(flatpak remote-info:71966): GLib-CRITICAL **: 15:38:06.886: g_utf8_strlen: assertion 'p != NULL || max == 0' failed
    Commit: (null)
    Parent: a459779fdde9defdf18be8e9277a1d3f5ba13bbfc190f86a930fe4ad578b2d89
   Subject: Appdata: add a patch to fix it (974981c3)
      Date: 2019-09-13 15:18:14 +0000
   History: 

Expected results:
No critical message and the Commit is not (null)

Additional info:
G_DEBUG=fatal-criticals gdb flatpak                                             
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Reading symbols from flatpak...
Reading symbols from /usr/lib/debug/usr/bin/flatpak-1.8.2-2.fc33.x86_64.debug...
(gdb) r remote-info --log flathub org.gnome.Eolie
Starting program: /usr/bin/flatpak remote-info --log flathub org.gnome.Eolie
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
[New Thread 0x7fffe8dac640 (LWP 22974)]
[New Thread 0x7fffe3fff640 (LWP 22975)]
[New Thread 0x7fffe37fe640 (LWP 22976)]
[New Thread 0x7fffe2ffd640 (LWP 22980)]
[Thread 0x7fffe2ffd640 (LWP 22980) exited]
[Detaching after fork from child process 22989]
[Detaching after fork from child process 22991]
[Detaching after fork from child process 22993]
[Detaching after fork from child process 22995]
[Detaching after fork from child process 22997]
[Detaching after fork from child process 22999]
[Detaching after fork from child process 23001]

Eolie - Web browser

        ID: org.gnome.Eolie
       Ref: app/org.gnome.Eolie/x86_64/stable
      Arch: x86_64
    Branch: stable
   Version: 0.9.63
   License: GPL-3.0+
Collection: org.flathub.Stable
  Download: 12.9 MB
 Installed: 37.9 MB
   Runtime: org.gnome.Platform/x86_64/3.34
       Sdk: org.gnome.Sdk/x86_64/3.34


(/usr/bin/flatpak remote-info:22970): GLib-CRITICAL **: 12:25:31.376: g_utf8_strlen: assertion 'p != NULL || max == 0' failed

Thread 1 "flatpak" received signal SIGTRAP, Trace/breakpoint trap.
0x00007ffff7610d23 in g_logv () from /lib64/libglib-2.0.so.0
(gdb) thread apply all bt full

Thread 4 (Thread 0x7fffe37fe640 (LWP 22976)):
#0  0x00007ffff74a2a0f in poll () at /lib64/libc.so.6
#1  0x00007ffff7659d1e in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#2  0x00007ffff76086ab in g_main_loop_run () at /lib64/libglib-2.0.so.0
#3  0x00007ffff7c172c3 in server_thread_func () at /lib64/libpolkit-agent-1.so.0
#4  0x00007ffff7635ede in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007ffff75813f9 in start_thread () at /lib64/libpthread.so.0
#6  0x00007ffff74adb03 in clone () at /lib64/libc.so.6

Thread 3 (Thread 0x7fffe3fff640 (LWP 22975)):
#0  0x00007ffff74a2a0f in poll () at /lib64/libc.so.6
#1  0x00007ffff7659d1e in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#2  0x00007ffff76086ab in g_main_loop_run () at /lib64/libglib-2.0.so.0
#3  0x00007ffff78476b6 in gdbus_shared_thread_func.lto_priv () at /lib64/libgio-2.0.so.0
#4  0x00007ffff7635ede in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007ffff75813f9 in start_thread () at /lib64/libpthread.so.0
#6  0x00007ffff74adb03 in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7fffe8dac640 (LWP 22974)):
#0  0x00007ffff74a2a0f in poll () at /lib64/libc.so.6
#1  0x00007ffff7659d1e in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#2  0x00007ffff760641f in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#3  0x00007ffff7608031 in glib_worker_main () at /lib64/libglib-2.0.so.0
#4  0x00007ffff7635ede in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007ffff75813f9 in start_thread () at /lib64/libpthread.so.0
#6  0x00007ffff74adb03 in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7ffff62dd940 (LWP 22970)):
#0  0x00007ffff7610d23 in g_logv () at /lib64/libglib-2.0.so.0
#1  0x00007ffff7610f8f in g_log () at /lib64/libglib-2.0.so.0
#2  0x00007ffff7635508 in g_utf8_strlen () at /lib64/libglib-2.0.so.0
#3  0x00005555555e03ce in ellipsize_string_full (text=<optimized out>, len=108, mode=FLATPAK_ELLIPSIZE_MODE_END) at app/flatpak-builtins-utils.c:1006
--Type <RET> for more, q to quit, c to continue without paging--c
        ret = 0x0
#4  0x00005555555a51ee in flatpak_builtin_remote_info (argc=<optimized out>, argv=<optimized out>, cancellable=0x0, error=<optimized out>) at app/flatpak-builtins-remote-info.c:309
        formatted_commit = <optimized out>
        len = <optimized out>
        store = 0x5555556f80d0
        app = <optimized out>
        license = <optimized out>
        rows = 35
        cols = 120
        width = 108
        version = 0x55555819ca44 "0.9.63"
        context = 0x555555709400
        dirs = 0x5555556ffc40
        preferred_dir = 0x5555556fb020
        commit_v = 0x7fffdc009660
        remote = <optimized out>
        pref = <optimized out>
        default_branch = 0x0
        kinds = <optimized out>
        matched_kinds = (FLATPAK_KINDS_APP | FLATPAK_KINDS_RUNTIME)
        id = 0x555555718940 "org.gnome.Eolie"
        arch = 0x0
        branch = 0x0
        parts = 0x555555703430
        kind = FLATPAK_KINDS_APP
        ref = 0x555555906fa0 "app/org.gnome.Eolie/x86_64/stable"
        commit = 0x0
        parent = 0x5555571f8540 "a459779fdde9defdf18be8e9277a1d3f5ba13bbfc190f86a930fe4ad578b2d89"
        state = 0x555555739b40
        friendly = 1
        xa_metadata = 0x55555581d0a0 "[Application]\nname=org.gnome.Eolie\nruntime=org.gnome.Platform/x86_64/3.34\nsdk=org.gnome.Sdk/x86_64/3.34\ncommand=eolie\n\n[Context]\nshared=network;ipc;\nsockets=x11;wayland;pulseaudio;\ndevices=dri;\nfilesy"...
        collection_id = 0x55555581cf00 "org.flathub.Stable"
        eol = 0x0
        eol_rebase = 0x0
        metakey = 0x555558bcc4c0
        installed_size = <optimized out>
        download_size = <optimized out>
        formatted_installed_size = 0x555557661940 "37.9 MB"
        formatted_download_size = 0x555557661960 "12.9 MB"
        subject = 0x55555581d3e6 "Appdata: add a patch to fix it (974981c3)"
        timestamp = <optimized out>
        formatted_timestamp = 0x5555576ac390 "2019-09-13 15:18:14 +0000"
        sparse_cache = {base = 0x7ffff7886b44, size = 140737345459717}
#5  0x000055555559d52d in flatpak_run (res_error=0x7fffffffdb18, argv=<optimized out>, argc=<optimized out>) at app/flatpak-main.c:783
        command = 0x5555556c4950 <commands+1680>
        success = 0
        error = 0x0
        cancellable = 0x0
        prgname = 0x5555556dcfb0 "/usr/bin/flatpak remote-info"
        command_name = 0x7fffffffe140 "remote-info"
        polkit_agent = 0x5555556fae50
        __func__ = "flatpak_run"
        error = 0x0
        ret = <optimized out>
        action = {__sigaction_handler = {sa_handler = 0x55555559e540 <handle_sigterm>, sa_sigaction = 0x55555559e540 <handle_sigterm>}, sa_mask = {__val = {0 <repeats 16 times>}}, sa_flags = 0, sa_restorer = 0x0}
#6  main (argc=<optimized out>, argv=<optimized out>) at app/flatpak-main.c:888
        error = 0x0
        ret = <optimized out>
        action = {__sigaction_handler = {sa_handler = 0x55555559e540 <handle_sigterm>, sa_sigaction = 0x55555559e540 <handle_sigterm>}, sa_mask = {__val = {0 <repeats 16 times>}}, sa_flags = 0, sa_restorer = 0x0}