Why can't I set the "VERSION" attribute for a "TASK" work package, which has "ASSIGNEE" field selected?

For example, for "USER STORY" work package I can do this. 

I can set the "VERSION" attribute for a "TASK" work package, which has "ASSIGNEE" field selected, only via "Bulk edit" menu item.

Up! Anybody can help with the answer?

Dear Alexey,

could you please tell us the steps to reproduce this and maybe provide some screenshots? I couldn't reproduce this situation with the given information. Have you already checked the user's permissions?

Screenshots in the attachment. The first screenshot shows an error for the package with TASK-type. On the second screenshot the same package, but with USERSTORY-type, and there is no error

Dear Alexey,
thank you for providing the screenshots!
In the Backlogs module work packages can only have children of the same version and the same project. To avoid displaying different information in the backlog and in the boards view this restriction is in place. You can solve it by disabling the Backlogs module or by changing the project (and if necessary version) of the work package you'd like to move.

I hope this helps?

Kind regards

Matthias