After changing the port name for a device worker spec, rebuilding the device worker, platform, and assembly, ocpirun could not run the assembly, stating that the newly generated bitstream wasn't compatible (specifically, that the newly generated worker did not have a port with the new name). After further inspection, it turned out that there was an old bitstream in the library path that did not get regenerated after the spec change. Ocpirun detected that bitstream, but did not continue searching afterwards. Removal of this old bitstream caused the new one to work.
It's unclear whether an exception was thrown when ocpirun saw a bitstream with the old spec or if this is the expected behavior. In the very least, a better error message should be used here.