The setup is a little more involved so it's not very easy to shrink this down, but the gist of it is that I create a representable, load local resources, evaluate JavaScript and use WKScriptMessageHandler for communication. The only easy workaround I found that eliminates the problem is to produce a .dynamic library from my package. How could I test DYLD_FALLBACK_LIBRARY_PATH for the Mac? (all info I see is for the iOS simulator). Thanks for your prompt replies, I appreciate the feedback!