This is strange. I have a workspace with security setting “lock project” which means no new task is possible. Nevertheless the “new task” button is visible. I think that’s an issue. It’s the same for “lock task”.
When I try to create a task I get an error message with resource access forbidden.
Can you check this ? I think in this case the “new task” button should not be visible. I’m pretty sure that this was the case in the previous versions, at least before 5.0