I'm running into some trouble in the last couple hunts where the X-1 probe on my E-Trac has been chirpy and falsing a lot as soon as I flip the switch on it. It used to be rather quiet unless there was iron or some other metal around but suddenly it seems to want to make high pitch noises no matter what I do or what it's near. Has anyone else run into this? It will still make the right sound and consistent noise when put directly next to metals but chirps randomly and oddly in most other situations. Could it be due to humidity? It's been brutally hot and humid here over the last few days. Is it defective? Any help greatly appreciated.