This issue should be hopefully solved in ModemManager 1.10.6 after adding several new heuristics to the "strict" filter mode. Also, the logic behind ID_MM_DEVICE_IGNORE was updated and this udev tag is now applicable in all filter modes (including "strict") and for all device types (not only TTYs).
MM 1.10.6 release notes: https://lists.freedesktop.org/archives/modemmanager-devel/2019-September/007424.html -- Aleksander https://aleksander.es
