Identifying duplicate time entries

Hello!

I am working ith a database that is timesheet entries for an organisation of about 80 people. Power Bi collates all the entries into one large database and then we can filter based on staff or team etc. It works really well!

One challenge we have identified is that some staff are making duplicate entries (as the database is just a secondary outlook calendar). I am trying to use DAX or M to identify these duplicate entries so they can be reported on.

This is the format I am working on:

I also have an identifier column which is in the format of calendar/name   (and I have ensured each person has a unique name e.g. JohnP, JohnR etc)

Can anyone assist me in identifying duplicate time entry?

Thanks in advance!