Resolution:

After loading paper from the rear paper path the printer will print for 
approximately 4 inches and  then pause, reverse feed the paper and pause, 
then feed the paper forward to the last print position and continue printing.

This only occurs with the rear paper path and is NORMAL operation for the printers.

The printer performs this operation to disengage a set of pick rollers 
that are used in assisting the loading of paper from the rear path.  
These rollers are located under the platen towards the back of the printer.  
In conjunction with the platen, the rollers grip the incoming paper and 
push it forward through the rear path and around the platen.