everything worked normally, I was taking snapshots incrementally with the vm powered down
and after the last reboot I got
kernel: EXT4-fs error (device sda2): ext4_mb_generate_buddy: 802 EXT4-fs: group 32, block bitmap and bg descriptor inconsistent: 32350 vs 32351 free clusters
EXT4-fs (sda2): Remounting filesystem read-only
restoring snapshot does not help
server is esxi 6.5.0 Update 3 (Build 14320405)
thanks