That takes me back 40 years, I did a lot of work for a builder and installed several tens of immersions in a development.
We had a batch of stats which intermittantly shorted to the brass case as they switched, they tested good when open or closed but shorted at the transition. It took a bit of finding but we convinced the manufacturer and ended up changing the whole estate. Another of those, seemingly, long forgotten memories.
Thanks for coming back with the conclusion.
