Thanks everyone for chiming in

On my outbound ticket with united domestic as first sector followed by BR and TG international sectors, it shows 2 free bags each 70lbs (32kg) . I did not see any mention of which carrier decides the baggage allowance

On my inbound, starting with TG and connecting to BR, it says baggage allowance is governed by Thai Airways and shows 2 free bags at 50lbs (23kg) each.

I checked Thai site and it shows for Royal Silk Class (Business) it is 2 bags each 70lbs.

At this point I am guessing it is a minor glitch on UA website, but wanted to check with the resident experts.