Regarding Nord on v7.6 I started a separate thread here: http://forum.mikrotik.com/t/client-vpn-nord-migrating-from-ikev2-ipsec-to-wireguard/163030/5 - this then has some really handy comments, one of which explains the differences. Our configs appear slightly different, so perhaps did not impact you. This migration is however a project for a rainy day for me!
I just had a freeze in my connection, hopped onto the Mikrotik UI and a rekey had just happened and there were brand new SAs…so can’t be a coincidence. However, the connectivity did resolve itself soon after without a manual clearout..which is also a bit of a first
Really stuck trying to understand why this can be so ungracious at times, however, it’s way more reliable in the last 48 hours - wether or not that is just by chance remains to be seen