Set off on spot golss UV (sreen)

[schmutz]

Job was printed with 4 col conventional offset inks, (veg. based) and solid satin aqueous on top. Backed up the day after, so we had 1 day drying in between.
Send to our local Screen printer and spot uv'd 1st side that day and backed up the following day, all stacks were uv'd in very small stacks ( about 400 sheets in a stack).A s soon as they finished off the 2nd uv pass job came straight back to us so we were able to get some "air" in to the sheets. Every sheet was sticking together, we were airing the sheets every 10 min but to little to late, damage was done, complete setoff off the gloss uv ( even after 1 week the sheets still sticking together) (Stock was 150gsm matt)
I am not an expert in UV but came up with some good ideas , perhaps never can proof it as the uv got done outside. Can anyone share some light in that issue? Any comments/ feedback are mostly welcome.
Thanks

 

[AKJ]

I would check with the Satin AQ vendor it sounds to me like that is the cause. Possibly miss labeled drum. Or if its a drum you have run more than once water could have got backed up into it.