A little update from my side as well.
A few days ago I started performing some actions on the blocked account (it got unblocked eventually) and it was ok till I tried to give JV anoher shot, because I haven’t really used it for a long time.
So I added the account to JV and bam - blocked immediately without any actions. I thought that the problem is with my account again, so I added my colleague’s account with a mobile proxy (he’s never botter, but he’s pretty active on Instagram, meaning liking and commenting on posts, no growth intensions) and after the first 5 follows he got blocked as well, and that’s the first time he gets blocked. Note that I have let it rest for a day before attempting any follows. Then I added a third account with residential proxy and the moment it got verified it got blocked too without any actions performed.
Any ideas here?