See below.

Reproducible: Always

Steps to Reproduce:
On a system where glib2-{,devel-}.{x86_64,i686} are all already (forcibly) installed:

# dnf update glib2*

Actual Results:  
Last metadata expiration check: 0:05:40 ago on Fri 10 May 2024 08:52:33 AM CEST.
Dependencies resolved.
===================================================================================================================
 Package                     Architecture           Version                          Repository               Size
===================================================================================================================
Upgrading:
 glib2                       i686                   2.80.2-1.fc41                    rawhide                 3.1 M
 glib2                       x86_64                 2.80.2-1.fc41                    rawhide                 3.0 M
 glib2-devel                 i686                   2.80.2-1.fc41                    rawhide                 1.5 M
 glib2-devel                 x86_64                 2.80.2-1.fc41                    rawhide                 1.5 M

Transaction Summary
===================================================================================================================
Upgrade  4 Packages

Total size: 9.1 M
Is this ok [y/N]: y
Downloading Packages:
...
Running transaction check
Transaction check succeeded.
Running transaction test
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: Transaction test error:
  file /usr/share/gir-1.0/GLib-2.0.gir conflicts between attempted installs of glib2-devel-2.80.2-1.fc41.i686 and glib2-devel-2.80.2-1.fc41.x86_64


Expected Results:  
Success.

This problem is not new to Fedora 41, just where I tried it now.
I usually just install the rpms downloaded to the dnf cache with --force and all is good, but it would be nice to not have to do that on every update.