It is not logged anywhere under /var/log/veeam/* but it's present in the veeam cli:
O.S. & Veeam Info:Veeam Agent for Linux [ ghost-nb-samsung ]
Backup 100% Status: Warning
Summary Data
Duration: 00:10:23 Processed: 2.7 GB (100%)
Processing rate: 21.7 MB/s Read: 2.7 GB
Bottleneck: Source Transferred: 899.4 MB (3.1x)
Time Action Duration
19:21:42 Backed up nvme0n1 1.6 GB at 271.9 MB/s 00:00:05 ↑
19:22:50 [warn] Failed to update grub in backup │
19:23:10 Backing up summary.xml 00:00:00 │
19:23:13 Releasing snapshot 00:00:02 │
19:23:15 Applying retention policy 00:06:36 │
19:23:15 Full backup file merge completed suc... 00:06:35 ▒
19:29:51 [warn] Processing finished with warn... ↓
# rpm -qa veeam\*
veeam-release-fc24-1.0.8-1.x86_64
veeamsnap-5.0.2.4567-1.noarch
veeam-5.0.2.4567-1.fc24.x86_64
# head -2 /etc/os-release
NAME="Fedora Linux"
VERSION="35 (Workstation Edition)"
# uname -r
5.15.14-200.fc35.x86_64