I would take out the WSE switch and clean with warm soapy water and then rinse and let air dry out in the sun. I would also remove the neutral safety switch on the right side of the tranny and take apart and use a 600 gritt sandpaper on the contact until they are flat across and then put a bit of stretch on the contact spring and clean out all the old grease and relube with a good silicone grease. Remove the connections at left side of tranny and lube with silicone grease and I think that will solve most of the problems.

Due to the switch location, a common problem is dirty switch.....spilled drinks, crumbs, general interior filth, etc. As it is a random occurrence the expectation is that the system is operating. While you are in there also check cleanliness and operation of the PRNDL switch and fluid color/condition.