Hi all. I have a difficult to reproduce issue with building an uberjar, getting the error, at runtime, “clojure class cannot be cast…” where obviously the class names are the same but one is loaded by DynamicClassLoader. My conclusion was that I was getting a class AOT compiled AND dynamically compiled. I ran build again, and it worked. I was using a single namespace in compile-clj’s ns-compile. I seem to have fixed the issue by either adding the problem namespace explicitly in ns-compile or not using ns-compile at all and letting :topo do it's magic. I've only ever got the class cast error at the REPL previously. I've stupidly deleted the problem release but may be able to reproduce the issue if I recreate the conditions and build a few times. Is there a potential race condition or something similar that might cause that? In the meantime, I'm inclined to not use explicit ns-compile options at all.