Benoire:
God I'm glad I currently have v6 disabled as I'm on static v4 and v6; most likely would be causing the same headaches! I'm tempted to turn v6 back on but I'm in teams meetings all afternoon and it probably wouldn't be good!
I was migrated a week or two back... I have a static IPv4 too. Mine went way more smoothly than some reports here. I did have to modify some Mikrotik configuration to get connected again (expected). My static IPv4 came across as did the same IPv6 prefix.
So its not bad for everyone.