I may need some help:
I didn't find the solution nor the information about a 'known issue'.
I recently updated several IP335 to 188.8.131.5262 (bootroom 184.108.40.2067) (asterisk 11/scopserv)
A customer called me for a problem they have: the 'Do not disturb' is shown on the display and can't remove it.
I got the same problem with the same phone model/version (IP335) here in our demo room.
Via the menu: enable/disable doesn't do anything also (not only the display, but the phone with dnd enabled is still reachable, it rings), also a restart doesn't fix the 'display' problem.
welcome to the Polycom Community.
The easiest way to find this out would be to setup a wireshark trace and then reboot the phone and check the SIP Signaling.
Maybe Server controlled DND is activated or wrong / old configuration files have been used.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
If official support is required please check how to phone or open a case here----------------
I finally found the solution:
It comes from the idle screen of the micro-browser.
Indeed, the page shows the status of the Do not disturb (first line) and the Call Forward.
I didn't guess it quickly. It's when seeking for directory problem that I found the solution.
You can close this case, thanks.