Originally Posted by Shardancalibre
When you say : ... the book was present in both shelves, when I eliminated it from the shelf I didn't want it to be in, the book vanished completely (from the e-reader).
do you mean you just unchecked the book from one shelf and left it checked on the other or did you delete
it from a shelf ? If the latter then it's effectively gone from your eReader.
If the former then I don't understand