Scanning items sometimes does not scan right away

The plinth sometimes does not scan the item right away.  There were times when I was trying to scan an item like migrate or a fiery elemental on an animal where the firefly is, but it didn’t scan it or scanned late after the firefly had moved on to another animal.

Not sure if this is a software issue or I’m just not putting the item close enough to the scanner (which I think I do).  I’m putting it out there in case somebody else had similar experience.