Another failed sensor but I have a question

[Tman]

I too had a bad rear sensor from march 2014 , double tape installed , i opened it to see since it was out of warranty .
Surprise : water inside + rust over the receiving diode.At first view the outside shell did not show any sign of
broken/damaged seal.
I have pics if anyone is interested.

I had another from 2016 , double side tape , which i did not open , was replaced under warranty .
I did not hear feedback what was the reason for failure , would be interesting to learn the diagnostic from the manufacturer.

The sensors are well insulated but not enough in my opinion.