Everything ok today, didn't change anything. Probably it was pool/miner problem.
Thanks for the heads up I'll check it out, would very much like to be mining lyra2rev2 right now instead of other algos with my cards, especially with networks needing all the hashrate/security they can get with the spate of 51% attacks coming from nicehash.
EDIT: 5/30/18 Seems the newest version (3.10) is now working normally again for me. I've not yet run it overnight, will report back with longer term results.
Edit: 6/1/18 The behavior of the v3.1 mkxminer is back to what it was before May 21rst.