ACL permissions on external HDD lost after reboot

rfb - about 1 month ago -

I use the Transmission CLI and it creates a transmission user and group to deal with torrented files for security reasons. So, I set up a shared download directory on an external HDD with the proper permissions for it (as explained in the Arch Wiki). However, the drive itself is mounted at /run/media/my_username/hdd_name with regular rx permissions for everyone except at the my_username level where permissions are set through ACL and can’t be accessed by transmission by default.

So I set the r-x permission for the transmission user for the my_username directory (again, following the Arch Wiki instructions). All is well, even when I remove the drive and plug it back in during the current session. However, when I reboot, the new ACL permission is lost and I have to use setfacl again for each new session. The drive is always mounted at the same location and its filesystem is ext4 (like my main SSD).

How could I set ACL permissions so they can be persistent across reboot?

Many thanks,