Did you flag errors to be caught as per documentation? e.g.
catch_error_init();
catch_error_set_normal(catch_error_normal_queue);
catch_error_set_fatal(catch_error_fatal_queue);
Edit: You seem to be. What runtime version, and could you assemble a small sample project that reproduces this? Don't think I've seen "malformed variable" errors outside of literal memory corruption