It is possible to write methods that are not safe to interpret (and Base has a few of them). These are special cased to run compiled by putting them in JuliaInterpeter.compiled_methods or JuliaInterpreter.compiled_modules (for compiling all functions in a module).
You can try pushing the method causing the error into JuliaInterpeter.compiled_methods or whole of PyCall into JuliaInterpreter.compiled_modules if you don’t want to debug anything going through PyCall.