If I understand correctly, you spliced the new sensors to the existing wires going to the operator. If that's the case, the problem may be a pinched wire.

If the wires are stapled too tightly to the door frames, which is common, they can be pinched by a staple, breaking the wire internally. This can show up after a long time or even be intermittent.

Check each wire carefully for staple pinches. If you find one, you will probably find more. If it is only pinched in one place, you can splice in a repair section. If there are multiple places, I suggest replacing all the wires.

The problem could also be in the operator.