Bug/Issue Invulnerable Mummies

I've been playing Stardew Valley on Nintendo Switch for while now, but I only recently found some kind of bug while exploring the Skull Cavern.

I recently encountered a couple of floors with a large number of mummies on them, but that's no big deal. The issue comes to slaying them. I've found that, upon attacking and reducing more than one mummy to a temporary pile in the same swing with my Galaxy Sword, one will remain in a pile, while the ones who were also supposed to enter this state will immediately reform and proceed to attack the player character.
I messed around with this a little and found that not only can it occur to multiple mummies at once, but those which do immediately reform will be completely invulnerable. All attacks miss them. The only way I was able to temporarily fix this was by swinging my pickaxe at them, which caused them to take a small amount of damage, before switching back to my Galaxy Sword and swinging at them again, dealing damage once more.

I'm unsure if this glitch may be affecting players on other platforms, as I haven't actually found anyone mention this glitch beforehand.

 

i have the same glitch on pc