Panorama

"it creates 3 seperate panos, one for each photo I've selected."

This will happen if each of the 3 photos are at the top of their own stacks. When you select multiple collapsed stacks, Photo Merge will process the photos in each stack separately.  Either expand the stacks and then select just the photos you want to merge, or remove them from the stacks.

If this doesn't help, please post a full-resolution screenshot (not a cell-phone pic) of the entire LR window in Library after you've selected the photos but before you've invoked Photo Merge.

Try going back to redo images you know have worked before. That will help you determine if it's LrC or the actual images that are the cause.

I also recommend resetting the LrC preferences anytime the app does not work as expected.

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

<"moved from cc desktop bugs">

So sorry, it's LR Classic, all updated.

what app?