failed LVT

hi can anyone help,....laid moduleo large plank on ke49 and just recently customer rang to say there's bubbles appearing in it...it's on an underfloor heating et system which has been on around 16 degrees...but has recently been turned up to 20

 

Are the bubbles definitely just in the lvt and not the screed?

 

looks like just in LVT...screed not blown

 

Was the sub floor dry enough before it was laid

 

Ive always found the moduleo to be too 'sheet' like, almost to soft and floppy!!

Take a few up and you'll see whats what from the adhesive print first off

 

tested it with tramex meter...it was around 1.5%cm