You might be loading two sets of Qt binaries into the same process. Check that all plugins are compiled against the right Qt binaries. Export DYLD_PRINT_LIBRARIES=1 and check that only one set of binaries are being loaded.
QObject::moveToThread: Current thread (0x7ff56d74feb0) is not the object's thread (0x7ff570dfec60).
Cannot move to target thread (0x7ff56d74feb0)
pip uninstall opencv-python
pip install opencv-python-headless
pip install --default-timeout=50000 opencv-python-headless