The "Security" field is now invisible for some reason (no idea why, I haven't seen this mentioned anywhere), but it clearly still exists, and the value can't be changed (since it's invisible in the editor too).
Task T153217 (which is public) has this field set, and because of this, H173 is removing @Poyekhali as subscriber from that task.
Ping @mmodell to change the security from Software security bug to none on that task. That'd solve the issue.
If I edit the task I can see the field, but I can't modify it. Maybe somebody from Security is able to do so too.
The security field no longer serves any purpose. We should just disable to associated herald rules.
H141 is blocking that. On the other hand, we may have Security tasks without Security, so we can:
Since the Security tag doesn't have any real meaning to the software (and never has) we should probably just stop fooling ourselves and remove the herald rule.
@mmodell: I'm afraid I don't understand the full implications here as I'm pretty lost in Phab's Security infrastructure now, so if you think so feel free to go ahead.
(Related random thoughts: Another example I don't know how to fix. And in https://phabricator.wikimedia.org/T162516 the user gets unsubscribed due to poor H173.)
ok I changed the security policy defaults on the security bug form, now the herald rule isn't needed (and I have disabled it.)
As a consequence, when a security task is made public, the default policy will be removed and the users mentioned in H173 will be once again allowed to see/subscribe to the task.