I've noticed something pertaining this which I assume might be a bug; when terrestrial planets have rings, they seem to be tidally locked
to said ring, with rotation periods in the order of 0.5 to 3 hours and the remark "1:1 Tidal Lock".
I could be wrong, but I don't think that's the intended behaviour.
What I
think might be happening:
For the purposes of Moon Tidal Lock DM calculation the code is counting the ring as a moon; depending on how you're dealing with the Expanded Hex format Traveller uses, it might even be converting the ring's "R" code into "25", pretty much guaranteeing a lock. Though this second part is entirely conjecture of my part, of course.