Weber said they redesigned their probes so they would last longer.  I threw away all my probes and bought 4 new ones.  2 months later doing the same thing the old ones did.  Reading 475-525 on a brisket still sitting on the counter not even in the smoker.  I dont know how this is possible. But it's time to trash it all and go to a reliable brand.  That's 6 probes I have thrown away.