Interesting. Let me know if it works for you and I will try it when the next update is available. Just make sure you don't reboot following installation of the update because you first have to go into Magisk and choose install / install to empty slot after OTA or you will loose root.
this didn't work unfortunately. gives you a message about not being able to validate the package. i'm sure there is a way around this but I haven't found it yet.