That is actually a very good adhesive and recently it’s formula has been upgraded to S1.
If sufficient notch size has been used (in this case if it appears that it is as you have 25ish ribs across a 600 tile) then poor coverage issues normally arise from an uneven substrate (which I’m assuming it’s not) but sometimes the tiles themselves may be ‘dished’.
The adhesive in your picture doesn’t appear to me to be skinned as it still appears wet. Try back skimming the tile in the same direction as the floor with a 4 or 6mm notched trowel also.
Thanks a mil Lee
One thing, if I add say a 4 mm notched more adhesive would the lipage be too noticeable with the one that are already laid? Is there anyway to overcome that?