The same thing happend to my two routers , one RB 750 and one RB751 . They were working fine couple of months but with the 5.13 version they’re not working any more. All my configuration were lost .
I don’t know what do CPU, because mirotik will crash and is not possible read cpu status. And little important think i have the same problem on 5.14.
What i read in this forum is a HW problem, but my reseller have problem with RMA. Something about 50$ for RMA from Mikrotik.
I don’t know, but I think that this 5.13 is corrupt. I have had this problem, and that I put your router does no longer 5.13 gone go and made reset. I give it to the my reseller and have replaced the me-new and currently is on the software version 5.11.
I think that bad software but also to section 5.14 is uncertain. I did not dare any more to put up any new software other than as the same thing could happen again.My reseller told that it is a software error and something related to overfully 100% CPU and router dead.
My suggestion, do the things that people here can be a leisurely time with regard to not worry about a router