That’s how I’ve used mine for the 3D, down the spout hole. No other way really. I’m gonna say it’s bad luck then because I wash mine the same way, sponge to the probe portion only and dry. Then I roll the wire up and back into the case I purchased.
When I use my WEBER kettle, I have tried a few ways of getting the probe inside, under lid, through the exhaust damper, and they are doing great.
Hopefully the next one works. I don’t see you doing anything differently than what I do.