Kitchen floor tiles lifting from concrete fllor

The bad tiles will have to taken out and refix😊

Tiles don’t normally lift in this way, so it’s worth trying to understand why. They will certainly have to be lifted to learn more. Possible causes might include movement of the concrete base (screed) or tiles being laid on a anhydride screed without taking the necessary precautions. So, the tile movement might only be a symptom of an underlying problem. The solution will depend on the cause.

You'll need to find out why they're lifting really, has the right adhesive been used? Is the subfloor breaking up or moving?

of course the answer is to replace the tiles that’s a given! i’d be more interested in how and why there lifting that much to be honest with you? i’d suggest you get a skilled tiler to come and take out and have a closer look at the screed and what was used etc. if you have underfloor heating and there was no anticrack membrane (ditra matting) or the wrong adhesive may have been used also!. if you get a gold ball and bounce it on the tiles around to hear what is hollow or stuck that may give you an idea on how bad it is.