FB700 Carrier rail issue

Any one ever have a problem with one side of the carrier rail losing height during printing? One side (left to right) of print is good the other side the carrier hits the material after an hour or so of printing. When I shut the machine of turn it back on it is good for another couple of hours. Any input would be greatly appreciated.

 

Replaced the service end carrier rail actuator (jack). Didn't work. Cleaned the carrier rail height encoder (I guess that is what it is) and has worked fine today, we'll see what fresh hell awaits me tomorrow. Question as to terminology. When you say re calibrate are you referring to the board settings? If so I tried that and it didn't work at the time. Thanks for the input, will post if it isn't fixed.

 

Wanted to wait until I had printed for a week or so until I updated the post. It appears that the issue was the vertical encoder strip (my definition) on the service end of the carrier rail on the input side. Have to remove the service end cap to even see it. I have since printed about 8000 sq ft of coro so I'm pretty sure it was the problem as I have not had any more issues. Thank you to those who offered their input, it has been greatly appreciated.