I had a similar situation with my tank and seat cowl. Decided to spray a coat of Barcoat isolator before getting down to actual finishing with primer and top coat. Because I’m basically a sad old fart – I stick to what I know – Cellulose.
Anyway the primer reacted with the Barcoat !!! Oooops – that’s not supposed to happen.
I was that gutted after all the prep and work – I couldn’t face hours,/ days of rubbing back and even then not being certain there would not be a future reaction. So – I had the tank media blasted back to bare metal [ £20 ] ! Yes revealed all sorts of dings and dents – but at least I knew I would be starting again without any lurking problems.
The seat was another matter as it was GRP – solution, buy another seat base ! [£35 ]