Detecting a target several inches off the front of the coil sounds like an on edge target to me. I just ran some tests on an EQ800 and it was the on edge targets that produced oddball behaviors including detecting the target several inches off the front edge of the coil. Stick with me for a moment.
I was trying to configure the EQ800 so that it would give me the equivalent of LONG TONES for beach hunting. I was testing Recovery speed 1-3 to give me the widest possible detection area around the coil. What I found is the Equinox even at these lower recovery speeds which should be detecting a flat coin several inches from the outer edge of the coil, it seems in the software the machine is shrinking this back down to about the size of the coil. When the target is flat, I was seeing maybe 1-2 inches in front of the coil depending on depth.
THEN I TESTED ON EDGE TARGES - Incredibly if the coin was on edge it was being detecting like 6 inches in front of the coil which would make them more difficult to pinpoint. These on edge targets, a Barber dime for example that I was testing, on edge targets were pretty much invisible to previous detectors like the Explorer so its a net new target I'll have to figure out how to pinpoint.
Equinox on edge targets UNDER THE COIL also behaved pretty strange in a way that would make pinpointing more difficult. As you sweep the on edge target I saw either a Quad beep (Park/Field 1) or a Double beep (Park/Field 2). As I swept over a on edge coin in Park1 or Field 1 the quad beep signal was this, 50 tones, Recovery speed 3...High tone beep, Low tone Beep, SPACE High tone beep, Low tone beep in a single swing. The SPACE in the center was when the coin was directly under the center of the coil. It was really detecting the coin 2 inches left of the coil center and 2 inches right of the coil center with no tone in the center. I could see how this would make pin pointing difficult in that you would have to focus on that space in the middle as the true location of the target. In Park 2 and Field 2 the double beep response was High tone SPACE High tone. That's with the on edge coin straight in line with the coil front to back.
Rings vs Coins on edge - First the Equinox likes coins on edge with their flat surface better than rings on edge with the big hole in the center. It seems the larger the whole e.g. the larger the ring it hates those more than smaller rings on edge. I tested one silver ring on edge that is really wide, its like 1/2 inch wide on your finger but thin, about the thickness of a dime. So looking down on it laying flat there's not much metal surface because its so thin. Still the thing is 1/2 inch wide patch of silver from on edge. I expected the Equinox to smack that ring HARD. Incredibly it hated that ring, horrible signal on edge.
That leads me to believe the Equinox when detecting on edge coins or rings, it seems to be detecting not so much the small top edge of the coin or ring, there's some signal coming from that, but I think more signal is coming from the side vs the top. The 15 inch WOT coil had a real knack for hitting deeper silver dimes tipped at 45 degrees from the side. Instead of the coil field striking straight down onto the dime, the magnetic field seemed to be curved at that depth just the right amount to strike 45 degree tipped dimes from the side vs straight down. Which also made pin pointing those difficult because the signal was shooting off sideways from the coin. Tip your coil sideways vs flat and try to pinpoint right.
Summary - now that we have a machine that can detect targets on edge, just realize they will behave quite strangely when you sweep them. No different than when I encountered a coin at 45 degrees with an Explorer and that angle caused the coin to throw a signal off half sideways which made pinpointing the target difficult. Anyway that's my 2 cents worth.