Oh that's indeed an issue. Someone encountered this issue before and I thought I had already fixed but but oh well.
I'll double check every instance the other characters are removed (mostly near the end of a chapter) and add a line reviving Lianna before removing them. Can you tell when it happened to you?
They should, as I copied their effect from one of the game's default item list. You only get one EXP message at the end of the fight, as the EXP is distributed to the whole party, but the goggles' buff is character specific, so I'd suggest you take a look at your characters' status screen. This is probably just an RPG Maker thing.
