I found 3 of these an I cannot figure out why someone would stick them to something to show their obverse. They all have epoxy on the back and similar lines on the obverse. Is there something here I'm not seeing?
No explanation is really necessary, or maybe not even possible. You should not think that there must be a logical explanation.
When you have billions of coins distributed among millions of people, they are used, abused or altered in every conceivable way. Perhaps part of an ill-planned project or display for reasons impossible to determine.