After opening the chamber last week, Mitch and I were finally able to get together to replace the V1 GS13, seems like the problem is probably fixed for now. First attached plot shows the passive tfs from the V1 and V2  gs13s to the tabletop Z T240. The brown trace is the old V1 gs13 before replacement, the red and blue traces are the new V1 and unchanged V2 sensor. The old V1 sensor had low response by a factor ~2 compared to the V2 sensor, the new V1 sensor now matches the V2 sensor, the V2 sensor's response hasn't changed. Prior to swapping out the sensor, we went through and checked all of the cables inside the chamber were secured, but didn't really find any explanation for the bad behavior of the old sensor.

I've done close out tfs, those seem okay, second attached image. If FC2 tfs are still okay, I think we are ready to close the chamber.