Uh oh..... Primer flaking from varnished timber

I did a job 2 months ago where the house was gutted and fully re-painted. All the timber was varnished pine and I painted it white.

I didn't want to use BIN on that size of a job so I got Colourtrend 2 which according to them is their waterbased version of the red tin of BIN..

I then put 2 coats of advanced satinwood on top. I got a call this eve from the owner saying the wood is peeling in spots! It has been hit in places and the paint just fell off... A window cill which got 4 coats all...

Uh oh..... Primer flaking from varnished timber