Adding a Cross to the plinth is not recognised

Hi,

with a few items on the plinth I then add a Cross, it scans ok, comes up on the screen “Action” Cross, I then add the cross to the items already on the plinth but it’s not recognised and remains waiting on the screen for the item to be added.

any thoughts as to what’s wrong or what i’m Doing wrong would be appreciated?

thx Jono