I noticed that on a larger than coin size aluminum target like a can that rings in high coin. After detuning the target the detector would almost detune the whole target out. You could just barely here a tone while Xing the target after detuning. After digging it was large and always aluminum. I also noticed that on some of the large targets and two screw caps that while pinpointing the detector would almost resinate and the bars would peg. I'm sure there are exceptions but the past 2 days I was aware of the way the 250 was trying to tell me not to dig. Have you noticed that before?