Not sure if this is a bug or intended functionality:
If the SMB share the backup is pointing to is unavailable (either the share is unavailable or the endpoint's network is disconnected) it obviously fails. When connection is reestablished and a backup is run, it runs a FULL backup, instead of an incremental. I have tested this a few times now, and can confirm after a failure due to a disconnect a .vbk is created instead of a .vib.
I know if you point the backup to a NEW location a VBK is created first (obviously) but this is the SAME location and existing VBKs/VIBs are visible to the application. Is this behavior intended or not? If it is intended, then I would prefer a VIB be created instead of a VBK, since I could see this being a drag on resources due to unstable network connections (such as WAN connections).
If this is NOT intended, I can also test via a USB 3.0 device I have handy, to see if I can replicate it there too, just need feedback first.