On the other hand, MikroTik devices do suck.
Ever had the pleasure of dealing with one of these pieces of garbage?
Not that Cisco doesn't have problems (FWIW, I admin a fair sized Cisco network), but MikroTik routers give me a feeling in my gut that it's just about to break, any minute now... I could build a better router out of a PC and some NICs (and have - love OpenBSD)...
Disclaimer: my experience with MikroTik is from dealing with a particular Indian Contracting firm that uses them, and they also happen to have incompetent admins (willing to give me admin on their boxes to fix their problems - told 'em to deal with their own gear)... Maybe that's a commonality between MicroTik users?
Sounds like STP was configured poorly and you had a switching loop. I've seen it happen where one switch is configured wrong and make another switch's CPU peg, especially if the other switch decided to advertise itself as the root bridge and it didn't make sense.
:set nohlsearch
"Ninety percent of baseball is half mental." -- Yogi Berra