Hi
I have been using the MVP by Bostik and BST Urethane glue.
I love to work with it but I have had one failure on a ground level concrete.

I have used this two products and the floor cupped.

Need an advice from a pro who does it a lot.
Thanks
Rafal

It may be that the wood was not acclimated to the room well enough and it would have cupped even if it was nailed down. The glue fastens the wood very securely.
There will not be enough elasticity for the whole floor to move if the floor wants to expand some with a change of conditions. If the floor is a little on the dry side and may expand to reach acclimation some minor gaps during installation will be a good thing. If the glue hasn't let loose from the concrete and the wood is secure it is the wood that is swelling as a result of the acclimation to make the cupping.

Well theres no water in MVP4 and Best, so why did it cup? Unless you used the wrong trowel for the MVP4, perhaps its dry cupping, a normal moisture imbalance from top to bottom if it's really dry air.

I use SikaBond T-21 with its sealer for wet slabs, or Bostik Ultra set, single step.