Someone stripped the finish too aggressively, thinning the soundboard/top plate. That compromises structural integrity, so the bridge is sinking into the softened top, lowering the string action beyond adjustment. This is a serious issue because the top plate is what transfers string energy into the body, and once it’s too thin, it can’t resist the downward pressure of the strings. Adding extra bracing is the most common way to salvage such an instrument, but it’s a delicate balancing act.

Guitar service
Guitar service - shorts

Mandolin Restoration.