Up scaling TID...nice to know this happens on the deus as well then. I believe this should be easy to check at what point the anomaly occurs, just do some air tests.
I find this happens on the Fisher alot, especially in coin spills. My theory (that could be totally wrong) is that as detectors are generally set for coin sized objects the signal projection around the objects meets in the middle as if the objects combined to deliver a target response, and I've seen this in my air testing. If I place a 5c piece on a 50c piece I get an averaged tone/TID, and less so if I place the 5c under the 50c but just next to the edge.
So on my screen I see 50...for 50c piece and 23/24 for 5c when they are on their own. When combined with 50c on bottom and 5c on top the response goes 50/40s/50, effectively giving the 5c a higher TID value.
If I place the 5c under the 50c I get a 50/42/38 as it passes from the 50 to the combined edge, but never gets to the lowest TID of 23 for the 5c.
As the targets are too close to the recovery point the detector "averages" the response based on the detection signal and response constraints of a coin sized object. Basically it's completely repeatable in both air testing and in ground scenarios. Maybe this hasn't helped but its certainly a consistent response in the F75 and I'm willing to accept in the deus this can also occur.