Conditional formatting messing up when I copy the original worksheet to another one

Hi
I have created a rota for cover of clinics and have added conditional formatting for when a name is entered onto the rota. The cell is simply filled with a specific colour when non-blank.
When I have copied the created worksheet to further worksheets to use on separate tabs for each month, it changes the colours all over without any text being inserted.

What am I doing wrong?