Nope not at all, I did the underside of my A4 and it was dry within a day. And I sprayed chassis components that again were dry within 12 hours. I all depends on how thick you put it on and how it's been mixed! They say if you spray a panel with 2K paint it takes weeks to fully cure and should not be machine polished until about 3-4 weeks later. I've sprayed panels and machine polished them days later with no issues.
I can only tell you that I've used the product, it works very well with no extended drying times that I have seen. It's also kept the rust at bay. I've got a restoration here where you can see the results.
https://www.audi-sport.net/xf/threads/audi-a4-restoration-rebuild-thread.420769/ I would say that the silver epoxy did take longer to dry than the black for some unknow reason.