I am fearful that might be the only answer "pcm replacement". The PCM has a look up table which tells it what the switches mean. The question is, is there anything that "triggers" the lookup OR is it a "scheduled" function (ie. every x msec). If it has no trigger and goes purely on the lookup and the lookup result is different, it just follows that blindly and starts changing things.... maybe. It doesn't sound quite right... as then I would think perhaps the PCM would be more bonkers... but you never know. Having said that the OP indicates other PCM "fault codes" which may indicate more problems with the PCM as it is hard to believe all WSS sensors are bad.
There is also some other components, which read gearing, internal to the tranny and feed that information outward.... but this is way beyond me.
To me the issue is more electrical than mechanical since stop and starting the engine gets some relief. Further, there is still some question around... did some work with the shift cable and now there is this problem... BUT I don't think I have seen a well defined "timeline" to "work done" things were this way and then things went this way days later... or whatever it actually was.
I almost get the feeling that the "cable change" was done as a first attempt at resolving this problem.... which it didn't. Then the switch was changed and that had no impact.
That's just my read though... OP needs to qualify things a bit.