Could not agree more. Offer codes are a complete mess to test and just simply do not work in most circumstances, judging from the other questions and lack of answers on this forum, I'm clearly not the only one with these issues. Offer codes were a breeze to implement in Android in comparison, I don't know why Apple makes this so hard.

Same issue here - 90% of the time after clicking the Redeem Offer button with a valid code it just stalls out (Redeem Offer button is greyed out) and doesn't do anything for about 60s. Continually clicking the Redeem Offer button and waiting will occasionally bring up the purchase sheet, but in our testing, only about 50% of these attempts actually move on to successfully redeem the subscription offer and present the screen to "Open 'App'" which hands it back to the app to finish the transaction process, which does happen successfully. In my opinion, this is clearly an Apple issue given that our subscription flows work correctly when the stars magically align. I would like to see at least some acknowledgment from Apple that this is an issue that is being addressed, but so far all I've seen on this forum is complete silence. The buggy nature of offer code redemption prevents us from actually distributing codes to our users as we know it will result in a large number of support cases with users experiencing the same problem. It's too bad because the process is so smooth and easy on Android in comparison.