I thought I would share this. 5 years ago I finished a mahogany transom with minwax ipswitch pine and then topcoated with polycyclic. For some reason it has held up well. Even though it is sold as an interior product. Wood that got the polycrylic without the stain shed the polycrylic in a couple of years and the wood turned grey. Could the answer be the stain sealing the wood which allowed the polycrylic to stay on the wood?