I've just tried this (Tor version 0.4.8.12) and it seems to be working fine for me. I've tested with both 8.8.8.8 and 1.1.1.1.
Which torsocks version? Yours is probably newer than mine. It seems to be a problem with torsocks 2.3.0 and only with dig. And indeed there is nothing wrong at the network level because I was able to do an MX lookup over tor using a different method than torsocks. I'm also able to use other apps with torsocks, just not dig all of the sudden.
I'm using Torsocks 2.3.0 and DiG 9.20.1
It could be the exit node that you're using perhaps? Maybe you could try specifying a different exit node and trying again. Also check exit node policies to make sure DNS is allowed, although as your problem only seems to be with MX records then that might not be the cause.
Exit nodes are temporary unless you deliberately pin them for a particular connection, which I have not done for the DNS servers. The problem manifests without exception for weeks now, so it could not be attributed to a bad exit node. The tor microdescriptor db tracks the perms of every node, so I don’t think it would create a circuit for disallowed traffic. There could be an inconsistency between the microdesc and reality, but it would have to be a replicated inconsistency for every connection attempted with torsocks and yet not replicated on any connection made using the torsocks alternative (which works).
Link to tor project (they made the icon I grabbed, and tor itself of course): https://www.torproject.org/
This is a community to discuss the tor project and your experience with tor, tor browser, etc.
Rules are generally: be nice, don't be bigoted, etc.
Only seems fair that an infosec instance should have a community about one of the most well known anonymity tools :)