@lucasbradstreet I was able to reproduce the exception locally running ZK server 3.4.9. With ZK 3.5.3 there is no exception.

I went back and did some dependency analysis on the version of our app that previously was working with 0.13.0, looks like an older version of ZK was getting pulled in which perhaps is what allowed in to work. I did try excluding ZK from onyx and pulling in an older version, but that so far has only led to stack overflow exceptions. Anyway, it does appear there is some backward compatibility issues with onyx 0.13.0 and earlier versions of ZK.