Unable to write to /run/mnt/ubuntu-data/system-data/_writable_defaults/etc/udev/rules.d/ on snapd rev 11844

It was requested that we add an install-device hook to our system's gadget snap that would provide the ability to inject a custom udev rule. Here is a link to where we were told to add the '/run/mnt/ubuntu-data/system-data/_writable_defaults/etc/udev/rules.d/' to our gadget snap - https://portal.support.canonical.com/ua/s/case/5004K00000E7LdyQAF/enabling-systemfile-interface-for-kdrpkdrpk4500gadget. NOTE: we are using a gated snap with snapd rev 11844. We have tested with the snapd rev on latest/stable and found that the install-device hook is executed successfully.

Through communications with the support team, we have verified the gadget snap is built correctly, and that the plug is available and set to auto-connect. We have also verified the gadget's assertion is up-to-date, and that the installation script checks/creates the directory defined by the plug within the gadget snap. I have attached logs of the failure.

A link to the kdrp-kdrp-k4500-gadget snap: https://git.launchpad.net/~reading-team/reading/+git/kdrp-kdrp-k4500-gadget/log/?h=20-keurig-kdrp