How to reproduce:
1. Create two new lists (say: Personal, MyList)
2. Create some item in 'Personal' list (say: a, b, c)
3. Select an item (say 'a')
   Now a sidebar with the delete button (details, date selection and other) is shown
4. Now go back clicking the back button.
5. Select the other list (MyList)
6. Click on New task entry

Result:
The item ('a') from the previously selected list ('Personal') is automatically inserted in the current selected list too ('MyList')