Mikrotik DNS don't support entries:
_ts3._udp.ts.something.domain 1200 SRV 0 9987 1.ts.something.domain
_ts3._udp.ts.something.domain 1200 SRV 0 9987 2.ts.something.domain

T.S. Client have info, can't resolve name ts.something.domain

DNS Cache is clean, only standards entries.

Please fix this.

My software is 6.20.

I found the problem and now it has been reported to support via e-mail.