I had been trying this thermometer to monitor temperature in my mash but found it unreliable. I just tried using it in a pork roast, then tested with a newer thermometer and it was way off. Should I try to contact the manufacturer or did I F it up?

If you got water in it you can try just baking the metal probe (leave the connector out) at 250F for half an hour or so. Then test again. Was able to recover a similar probe that wayThe junction between the solid stainless probe and the braided wire is not waterproof. You likely flooded it and it's done. You can get replacement probes for that one.
The junction between the solid stainless probe and the braided wire is not waterproof. You likely flooded it and it's done. You can get replacement probes for that one.
It looks like you have two channels. Did you try the probe on the other channel? From a website it shows that the temperature is up to 572 oF. For that temperature it should be a thermocouple. With a thermocouple there are two wires of different metals twisted together that produced different voltages at different temperatures. If I remember right that is the "hot" junction. At the probe input is the "cold" junction that is part of the measuring circuit. Maybe channel 1 is bad and channel 2 is okay. If a bad reading on channel 2 then it is most likely will be the probe.I had been trying this thermometer to monitor temperature in my mash but found it unreliable. I just tried using it in a pork roast, then tested with a newer thermometer and it was way off. Should I try to contact the manufacturer or did I F it up?
View attachment 879596