I am confused about the ability to 'assign' an issue.
I have created a permissionschema in which only two groups can assign issues - namely teamleaders and productowners:

When I login in and look at an issue as a developer I see two 'assigned' buttons next to the workflow dropdown. When I click on these, the buttons disappear and are replaced by a resolved button and its status becaomes assigned to the project lead. - image attached

So if I am logged in as a member of the developer group why do I still have the ability to assign? Why are there two assign buttons?
NOTE ADDED: Sorted the two buttons.. the workflow had an identical transition assigning the bug which was hidden under the the first one... not sure how that happened!! Operator error I guess... doh!! The permission part of this question still stands though...
Many thanks
Nick