EXP rates keep resetting

Hello all , i have came across a very weird problem that i have never seen before , the exp rates goes from 35x down to 1x after every hour to hour and a half its really getting old and pissing off all my players , if i reboot the server then it goes back to 35x but then after about an hour it resets again and i have changed the server.cfg many different way but it does not seam to effect it and still resets , has anyone ever had this problem before or know how to fix it ? or at least got any ideas on what else i can try ? thanks for any and all help guys