I'm still curious at the root cause here. FWIW, I wrote up the "clunkers' view of the DNS issues" here: ✨ Steering AI to use new manual.mikrotik.com - #16 by Amm0 for anyone curious.
On this one...
The mt.lv theory might have merit... I'd commented in new docs FEEDBACK thread should have a "7. Shortened URL using https://docs.mt.lv/... —> https://manual.mikrotik.com/docs" since the "manual.mikrotik.com" is kinda long. To which @normis has a curious response:
... which I thought was kinda odd response, since a DNS record and HTTP rewrite should not actually be hard for folks who make an OS and run DDNS/VPN/file-share services (BTH). IDK, but combine with the DNS issues, maybe @normis is was right.