Yep The Edge of Rusted iron will fool you on occasion.
I don't see what your using ,
But also On occasion it will be both a Coin & iron
most of the time if you change positions you can loose it, and
the longer you detect the more you'll make educated Judgements on weather to dig or Not.
But I must tell ya, I have in the last second thought "Definitely Iron",
"But what the Hail, may as well get it out the way",
& was surprised by silver.
I imagine machine as blind.
When it "feels" something of the possible proper shape and gives off aura of the composition its been told to look for,..the round head of a nail, a bent nail,when ran through possibilities is similar to what we,re after.Its roundish its metalish. The option is to ignore it.I,m willing to confirm and be on to next than risk missing a good target. Allways double check the plug you dug. Sometimes multiple targets.