It still makes reading but it always shows up with a error. My queston is how much damage can these take before you have to replace them?
Well let's see. You shot it, see the damage and it gives you an error each time. Sounds to me like you found out how much damage they take before needing to be replaced.
I think if it was me and I got an error every time that I wouldn't trust any readings and would be ordering a new sensor ASAP.
Did you have it at 100 yards, 300 yards or just set up for muzzle velocity?