This does appear to be a bug. I've opened a bug report for the policies team on Github (see issue 516) so that they can look into the problem.

Thanks!

See also:

• Bug 1559584 - Can't turn off updates using Group Policy or policy.json file

You can try to set:

• browser.policies.loglevel = debug

I broke this with our new menubar policy. Unfortunately I didn't make the new GPO available because it wasn't in the ESR yet.

I'm putting a fix into the next Firefox (Feb 11)

Is this a big enough issue you need me to do something sooner? I can create a custom GPO for the new policy on 72.