6890 FID column flow too fast

I have a 6890N GC with dual FID.  The back column has a much higher flow rate than the front column.  The two columns are identical and the setup for inlet, column and detector are identical. I have also swapped the EPC's between the two detectors.  Seems no matter what I do the flow is much higher on the back column than the front column as evidenced by very short retention times and  at least 3X higher readings on a flow meter. The pressures displayed on the GC all look normal! I know the flow on the front column is correct as the retention times match well with prior data on this GC and is a good match with other GC's we have in the department.  Is there a component that can fail and cause higher flow rates without an indication of higher pressure on the front panel?

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