I have noticed the message isn’t always accurate. Sometimes (probably when the element isn’t a line or rectangle) paths as terminals do not work, so the message perhaps should be changed to indicate that, although it won’t hurt to make the terminalIds not be a path, so perhaps we should change the part file format document to specify terminalIds can’t be a path (because some types of path won’t work)?
edit:
The same thing is true of paths as through hole pads in pcb. A path that is a circle (with nothing else!) works, but CheckPart will still complain that “no hole will be drilled” even though sometimes it will be. Again I expect the best solution is to specify that the pad needs to be a circle (not a path) in the part format file document.
Peter