Injection can fix floors, but it can blow up previously stuck tile too. It must be fixed or replaced.

FLOOR INJECTION works very well. If it's hollow underneath it is a great way to fix without having to pop them out and place or replace. Done well this is like micro surgery. After20 years of marble polishing one of my knees decided it was enough and popped. The first specialist wanted to replace, it would take forever to do , recuperate and it would never look the same as before. So I went for a private specialist. It was like going to the spa. The nurse held my hand, when I was in pain she yelped for me! It was done quickly, all done with needles like tools, cameras, 1 month I was back at work. That's when I got the idea to inject void areas in stone. No more ripping the floor opened, When you need to buy replacement tiles it never quite matches etc.
Day 1
Step 1 -look for cracks in your tiles or broken grout lines. This is an indication of hollow areas.
Step 2 - knocking on the floor will confirm it's hollow
Step 3 - Insert the micro epoxy needles
Step 4 - inject
Step 5 - Put weights over the injected area so the tiles don't pop up
You need to wait now so go make spaghetti.
Day 2
Step 6- Repair the grout. Jobs done .

PS the next day and for many weeks you may see wet spots. don't panic it's normal. that actually shows you how large the hollow area was.