terminate CAN

I'm having an issue on a MD4 where I have turned the terminate CAN off on all 4 busses but they still turn on the internal resistors. I end up with 40 ohms as I have 2 physical termination resistors already. If I power cycle the MD4 the resistance will be 40 ohms for a min or two and then it drops to 60 as it should be. then I power cycle the Md4 and resistance goes to 40 again and then drops after a min or two. Its seems like the MD4 will not take the changes but it has been set this way for several months and it has been reprogrammed dozens of times