On OSP16, RHOS_TRUNK-16.0-RHEL-8-20200224.n.0, with images taken from OSP15 (because of its exact size) I can confirm this issue, so I am assuming this problem "can" occur also in OSP16:
$ qemu-img info osp15/overcloud-full.qcow2
image: brew/overcloud-full.qcow2
file format: qcow2
virtual size: 3.84 GiB (4118413312 bytes)
disk size: 1e+03 MiB
cluster_size: 65536
Format specific information:
compat: 1.1
lazy refcounts: false
refcount bits: 16
corrupt: false
qemu-img-4.1.0-23.module+el8.1.1+5467+ba2d821b.x86_64
python3-oslo-utils-3.41.4-0.20200113095842.39870f6.el8ost.noarch
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2020:0657
Late but anyway, I can confirm that fix https://review.opendev.org/#/c/709588 for ironic-conductor container in RHOS_TRUNK-16.0-RHEL-8-20200225.n.1 deployment solves this issue.
Image:
qemu-img info images/overcloud-full.qcow2
...
disk size: 1e+03 MiB
On OSP16, RHOS_TRUNK-16.0-RHEL-8-20200224.n.0, with images taken from OSP15 (because of its exact size) I can confirm this issue, so I am assuming this problem "can" occur also in OSP16: $ qemu-img info osp15/overcloud-full.qcow2 image: brew/overcloud-full.qcow2 file format: qcow2 virtual size: 3.84 GiB (4118413312 bytes) disk size: 1e+03 MiB cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false qemu-img-4.1.0-23.module+el8.1.1+5467+ba2d821b.x86_64 python3-oslo-utils-3.41.4-0.20200113095842.39870f6.el8ost.noarch