Follow me time settings ignored sporadically

I have running on top of AsteriskNOW 2. When I setup follow me for an extension and Ring time set for 20, it happens as well at other values, and test everything works fine.

After a some hours or days, call to the extension will ring once and roll to voicemail. The logs indicate that no answer happened in 2000ms. If I disable the follow me commit and re-enable it, everything starts working again…for a while.

Any idea why the ring time is apparently setting itself to 2 sec?