Sometimes you may find that for tables sc_task or sc_req_item, the selection of criteria for Variables [+] shows up 2 times in the availability slush bucket.
This is visible in the classic report UI, but not in the new report UI. Additionally, if we filter for variables in the list view for the above tables, we can see that variables are appearing twice in the filter.
The dictionary entry for the variable field in task table is marked as active=true causes this behavior to get displayed.
Steps to reproduce :
1. Log in to the instance.
2. Proceed to system dictionary(sys_dictionary.LIST in the left pane navigation bar).
3. Search with the table as task and column name as variable.
4. Mark variable as Active = true.
5. Open sc_tak in list view.
6. Filter for variables. You can see two entries for the variables.
7. Open report builder classic UI, and select table as sc_task.
8. Check for variable+ field in the availability slush bucket. It should be available twice.
Marking the dictionary entry for the variable in the task field as active=false will resolve this issue(current OOTB setting).