I Have a 5.4l that has been misfiring on cylinder 5 but now the OBD is saying it’s swapped to cylinder 2, I have no idea what would cause it to swap banks completely as I just had the spark plugs done

 

Take it back to the people that changed the plugs..

 

Learning how to change mine recently in the 5.4 when changing all the plugs you have to remove the coil packs first, and not being numbered, my guess is that cylinder 5's pack was the issue, and now it's migrated to #2 upon reinstall. You could switch just the packs one more time and see if the code migrates again to be positive, or put a new one on 2 and return if not.

P.s. I am by no means qualified, just what I see. Godspeed 🙂

 

Your theory is a good possibilty.

 

Considering #2 is the second cyl on the right bank and #5 is the second cyl on the left bank, if the wires are long enough a mix up could have taken place.
Believe the alternator is in the way to do that , but anything is possible.

 

That's the best solution. Why give the shop an excuse to deny any mistakes which could have been done by them.