I was referring specifically to the referenced thread about the acrylic lenses warping when the inside of the car was warm and causing the needle to stick.

oh, got it! Think mine is glass and doesn't start moving until I drive for a bit. so weird

I sent the tach to J Bell and he was able to reproduce the issue on the bench so it was clearly an issue with the tach.

One of the boards had issues so john was able to replace it with a known good board.

Just got it installed and tested today, works like a charm

So thanks to John the car is now repaired and put away for the winter.