problem with task Permissions Management

Problem setting permissions for task

1- in “Permissions” screen for specific user or role I select “grant all” and press “OK” (image 1)

2- in “Permissions Management” screen, the “Permissions” column see “granted all” (image 2)

3- if click on “apply” button, “Permissions” column change from “granted all” to “custom” (image 3)

4- in “Permissions” screen for specific user or role only it appears checked “Task Application Root Page” and “Task Inbox Page” in “grant” column