rpath to Qt is not removed from dependent library using macdeployqt

I have the following setup:

• mylib.dylib -> depends on Qt
• MyApp (executable) -> depends on Qt and mylib.dylib

I'm trying to generate my MyApp.app distribution package using:

macdeployqt MyApp.app -libpath=/path/to/mylib

Everything works well, except for an rpath that is not removed to my local qt path in mylib.dylib.

This is problematic as Gatekeeper will not allow me to open my app (when downloaded from the internet) on macOS Catalina, even after (successful) notarisation.

(Note that I have not yet tested a more recent version of macdeployqt as I'm stuck with Qt 5.9.8, because I need to support macOS 10.10, but I expect this issue still exists in newer versions as I haven't found any bug report concerning this issue.)