Vodalex

Nothing strange. All software has bugs  and I don't fully exclude there is a problem with Armbian, just for this, I would say its probably on their side ... things are complex and is difficult to be sure without a research.

This means that OMV, which anyway completely changes OS, somehow breaks networking.
 
OMV was working well for many years, Armbian was even official partner ... As we didn't change anything in this regard, I would assume they changed something so try also to find this answer on their forums.