Upvote:2
Searching for that flight on China Airline's website doesn't have any warning about baggage.
When sold directly through an airline, you are certain that you are on a single ticket and that your baggage will follow you (short checking, which is picking your bag at a transit point, is usually a VERY pricey option (like $300/bag) to curb hidden-city ticketing).
I assume a glitch with trip.com, and anyway, I would NEVER recommend buying from an OTA (Online Travel Agency like trip.com), and only buy from an airline (unless the price difference is big, in this case think about it), it can save you many headaches.