A GM replied to my ticket which has now been RESOLVED. I discarded a ceremony invitation months ago using the companion app but it turns out the companion app maintains a discarded item reclaim tool for the last 35 items you discarded via this method. Since I had discarded it, it did not show on any item searches but it still prevented my transfer. I had to reclaim the item through the companion app and re-discard it in game in order to complete my server transfer. I wasn't able to find a resolution for this problem through any previous reddit or official forum posts so wanted to share what the fix was in case anyone else stumbles across this post in the future.

Please refer to the website below for more information on how to reclaim items using the Final Fantasy XIV Companion app:
https://companion-app.finalfantasyxi...uide/item.html