United seems to be telling me two different things here, though I am guessing the eTicket and United calculator are what I have to follow since they are in agreement.

If indeed it is just one bag (30kg), who should I contact to find out the cost for a second bag? Brussels Airlines, Thai Airways or United?

I booked an economy saver award, BRU-FRA-BKK-PER

The booking confirmation says this:

Calculate bag charges

FLIGHT Brussels, BE (BRU - National) to Perth, AU (PER) July 31, 2025
FIRST BAG Included
SECOND BAG Included
WEIGHT PER BAG 50 (23kg)

The UA eticket itineray/receipt says this:
Origin and destination for checked baggage Brussels, BE (BRU - National) to Perth, AU (PER)
1st bag charge 0.00 USD
2nd bag charge N/A
1st bag weight and dimensions66lbs(30kg) - 62in(157cm)
2nd bag weight and dimensions lbs(kg) - in(cm)


The UA website tool says this when I input the confirmation info:
Brussels, BE (BRU - National) to Perth, AU (PER)
First bag $0 66lbs (30kgs)
Second bag [blank]