I'm on my first play through of PoE 1 on Xbox. So, I was moving everything from a chest in Brighthollow to my inventory, which was full for that particular character, so I kept pushing 'x' to move everything to either another character or to my stash, which it seems to have 'confirmed' having done, and now all of those items are gone. I have looked over and over through each character, chest, and stash, in each stash option, under different organizational methods...I have even reloaded the game, but those items simply no longer exist. Am I alone in this problem? Am I missing something? Any thoughts?

Ouch, that's bad. Maybe check the Paradox forums (if there is one). Iirc they have done the console ports (Obsidian only made the PC versions). You can also check the Technical subforum here.

I didn't read about that big before. On PC you could occasionally lose one item - but never several and it happened very rarely.

I wish there was one forum that consolidated the bugs across the different ports - not a lot of people would be aware that Paradox did them, only that Pillars is an Obsidian game.