I've been using Sealcoat under WB finishes for over 10 years, almost always full strength. Only once did I have a crazing problem, and it was really minor and was over 3 or 4 coats of Sealcoat + Transtint toner coats. Used as a single coat sealer I've never had a problem, and that includes when used under EM-8000CV. Most of the time, however, it's been under GF's products. GF has similar warnings about using EnduroVar I over shellac; I've sprayed gallons and gallons of it and never had a problem.
As far as I can tell Sealcoat works fine under WB products.
John