Unexpected Voltage output on pin AB19

For this pin (AB19) we are seeing partial transition from 1.8 V to 1.3 V.

The good PCBA the upper level is 1.8 volt rail.
On a good PCBA, the lower level is ≤ 0.3 V.

On a bad PCB, the upper level is 1.8 volt rail.
On a good PCBA, the lower level is ≤ 1.3 V.

This level does not allow the remainder of the circuit to detect the lower level transition.