Time Log User Restriction - preventing time logging on specific tasks by anyone

Time Log User Restriction - preventing time logging on specific tasks by anyone

Hi,

I've only recently discovered the "Time log user restriction" feature in Zoho projects, and it appears like it will solve some big problems for us, but it isn't quite working:
If i restrict time logging to either "task and issue owners" or "associated team members", I can still enter time on tasks that I am not an owner or in an associated team, respectively.
Poking around i found that if i assign a task to another employee, or associate another team, then I am prevented from logging time on that task. This means the feature only works if i assign tasks to a team - if they are unassigned, they are essentially open for anyone to log time on.
I need to restrict users from logging time unless they are the task owner or in the associated team, even if  the task isn't assigned to someone else (which is what I had thought this feature would achieve).  How could this be done?

Thanks