Might want to check for forks...
I had a staking wallet that got stuck at block 390756 it appears it has forked at block 390747. Will reload the blockchain on this one.
BAD:
$ darknet-cli getblockcount
390756
$ darknet-cli getblockhash 390746
70699011048f44a66db1260f55e6c955b916d6cd6aa75afc333637db8958a554
.....
No issues with fork for me so far.
Had no issues with the switch to PoS level 4 - 3 wallets +15 MN

Had no problems here either. Payouts running smoothly.