The "Fetching item info" spinner never completes:

And the buyout price remains 0 (on realms where no pre-existing price data exists, otherwise it uses the last full scan price).

Inspection reveals that the ITEM_SEARCH_RESULTS_UPDATED event fails to fire. Various ways of trying to call C_AuctionHouse.SendSellSearchQuery have the same result. The vanilla UI works fine, so its likely there is a good way to call it.

Resolved. Turns out C_AuctionHouse.MakeItemKey(itemID, 0, 0, 0) creates an item key with a non-zero itemLevel, which breaks C_AuctionHouse.SendSellSearchQuery. Creating the item key directly resolves the issue.