Local policy doesn’t permit log interact

Is there a permanently repair to this problem?
Lan net with 2k server, and workstation w 2k pro. All this works fine until the day of the installation of the phones with IP, but the error only happens to a few and random, we can see PC policy says NONE, instead off EVERYONE, and if we change, after log off, sometimes goes back to NONE. Some PC’s never had this problem!