Did you fix it? Of not pls also report to https://feedbackassistant.apple.com/

We need help! Could not find a UI anchor for com.xxxx purchase. Purchase failed: Unable to Complete Request This log printed :(

I have the same problem as you. This must be a critical bug, users can't buy IAP, we are suffering huge losses.

Hi, I cannot install the iMessage app extension using TF. pls help

My solution is removing UIRequiredDeviceCapabilities key.