Game crashes whenever a large fill command is used & a sign is present

I used a fill command on a large area & my game crashed. I did it again on another area & the game crashed again.

Both times a sign happened to be in the area that was changed. I'm not sure if the signs are the cause, or maybe it's because they have to now drop their items because the block they were attached to is gone or what, but my best guess was to do with the signs being present