My friend and I put in this floor two years ago. It is Snapstone, snap together, floating floor, tile that is grouted after installed.
Prior to install, he used floor leveler in the hall area to come up level with kitchen area, where a door jamb exists. All seemed ok originally but I had a feeling that this door area would be an issue.
Here are my 3 OFF THE WALL, LOW COST IDEA/remedies: Scrape out the grout, then...
Spray loctite expanding foam underneath,then regrout.
Pour leveling compound to seep through underneath, then regrout.
Just try to regrout?
I have no more of these tiles left. This was a small budget project and I'm trying to keep it that way.
PS - Other than this, I LOVE this floor and product.