" I can see the ends of shims sticking out from under the tile "

Yeah, you will be tearing out all that tile as "shim" are not for tile floors. Pictures may help but it does not sound promising to me.

This is normal.

Cabinets are often set prior to flooring. Factory cabinets need to be "shimmed" up to floor level while most custom are built taller to compensate for floor thickness. Minor cracking is not unusual in concrete floor slabs but they usu have reinforcement to contain it.

Jeffrey R. Grenz, General Contractor the OP states the shims are under the tile, not the cabinets. Unless that was a typo.

@millworkman without photos we'll never know but I suspect the shims are under cabinets

I would agree, and in that instance absolutely correct. Lets hope that is the case and they are not literally under the tile itself.

Unfortunately not a typo.

We did end up tearing all the tile out and having new tile installed because the tiles around the removed cabinets weren’t very stable. It appears they tiled over the cabinet shims instead of cutting them off. Luckily no headaches waiting under the tile with the foundation. Thanks for the help guys!