Short of a wiring problem, that is not really possible. Can you explain how you have the sensors arranged in relationship to the magnet and how fast the magnet is moving between them?
The signal being generated by the sensors is correct as it works flawlessly in the loop code. The two sensors are about 10cm apart, and the magnet passes by them in about 0.2 seconds. Even after I unplug a sensor, the one pin will still trigger both startTime and endTime.
I appreciate your help.