I think you can get something called “veneer softener”?  Might help??
 
 
(I’d not heard of it either)

OFFS! Turns out there’s something called Veneer Softener!
Who knew!
Everybody but me, apparently.
 

I’m still accumulating little bits of advice fro across the internet. Here’s one from Airpress: “When a knife cut veneer (0.6mm) gets wet with glue – it expands. When it expands it buckles and wrinkles. Because of the flexible nature…   Read more»

@jamesbisset 
ha ha I’ve been using car body filler for years to cover up my poor mold making, so does that mean I’m a professional