UA's compliance with their disclosure requirements is awful. (To be fair, the requirements themselves are nearly impossible to obey).

Assuming this is the only flight on the ticket, as this ticket does not touch the US, the Most Significant Carrier (MSC) rule will take effect. The MSC on this itinerary is whomever markets (and thus operates -- marketing and operating carriers are the same on *A award tickets) the FRA-BKK segment. If that's TG, it looks like that should be a 30kg total weight limit (TG's fare classes are confusing things a bit). UA's systems are completely incapable of rendering total weight baggage allowances, so you get the kind of thing you were quoting where it looks like you get one 30 kg bag.