Facing an issue with Twin Column Select

I am facing an issue with Twin Column Select.
Suppose the left column consists of 4-5 items and I select one and click the button to move it to right.
The selected item moves to right column but the problem I am facing is that, along with the selected item another item which is just below the selected item is also moved to the right column.

Basically, it is not possible to move a single item rather it always pushes two items at a time to the right column.

This weird behavior is not observed in development environment but when the application is deployed on the server, it definitely occurs.

Could some one help to resolve this issue as this is very critical for us ?

Sounds weird.

It might be a long shot, but the only thing that comes to mind right now is that the Objects you are using as itemIds might have some funky .equals() or .hashCode() results, that result in both items effectively sharing the same id.

In my case I don’t think that the objects have same ids because if this is the case, then it should behave similar in development environment also.