If it's naming it to "0CUDP 1", that tells me that at least the {LOOP(PositionY)} part is working. I can only assume that the value you have in your loop settings in the "for each row x in" field is correct for the output of your List Files task - there's no way for me to validate that. Everything else there looks good to me, though. I also don't see an issue in your list of tasks - it seems to make logical sense. List the files, loop through the list and rename each one, then copy them all to a different location. Send an email if anything failed (I assume there's some sort of flow added to that task).
I just created a small task for me to try stuff. Here's the files before running the job:
And here they are after running the job:
I have the tasks set up like this:
Here's my List Files task:
And here's my Rename Files task: