T
The Legend; Phil Hobson RIP
All of the above sounds familiar. Nice to see Neal (Sir ramic) posting, hope you are well mate.
There's a good chance it was not dry. Natural drying would need around 20 degrees and 60% rh. The choice of adhesive puts you at risk and whilst SBR can be used it is sensitive to moisture as well. Sanding the floor to remove Laitance and any other surface detritus is essential for correct preparation. If the tiles are coming up clean it is a printer failure as that is the bit that is supposed to stick to the screed and the adhesive sticks to that in turn. You will need to lift the tiles and replace them. I would use a gypsum based adhesive. There are loads about and they are no more expensive than cement based these days.
What you are describing does not sound like Laitance. It sounds more like segregation which is a screed defect. You should not scabble screeds. They should be mechanically abraded which usually means sanding.