never used to be, perhaps they have changed there recommendationsOnly the subfloor was primed and then top of the XPs - as you say this may be part of the problem
Yes as I said I followed the Tiler’s advice who said SLC wasn’t needed - cowboy tiler !You can not say you followed Harry's advice you left out levelling before boarding .
Good luck cutting out 150 mm squares with approx 50 mm wire spacings