Oh, that's a brilliant find, GSchnitzer. Thanks. I'll be watching for more like that. Behind the scenes, then, were the patches removable from the shirts, or were they permanently sown on?
AFIK, the insignia were removed for cleaning each night - so it is very VERY likely that an occasional slip up happened.
TLOZ is a classic example, as Scotty's insignia switches back and forth a few times...I bet if you had the call sheets for that episode, you could pin it down by each day!