For what it’s worth I just found an issue between an RB922 running 6.48.6 and wap R AC 6 running 6.49.6 in mesh config the mesh connection kept breaking every 2-3 minutes. I tracked this down to a script that was doing a background scan every 2-3 minutes.
From here it gets interesting.
This script has been running with a duration=13s for years on the RB922s without breaking the mesh, but as soon as the duration exceeds 10s (on the wap r ac) it causes the mesh connection to be dropped and reformed.
I’ll submit this to MikroTik in a support ticket.