Conditional Formatting Duplicate Rows in Table that Adjusts with Filters

Thanks for taking the time to respond.

When I create that column, the output is 1, even when there are duplicates. The first row gives an output of 8 but every row after that is a 1.

I think I can see the same error in your first screenshot where the 'Number of occurrences' is given as 1 when there are duplicates visible.

Here is an example with dummy data. I have a list of Names, and have a Column to count duplicates (using the code in my other reply in this thread).

In the above situation, with all the data, every row should be highlighted as every Name appears more than once.

If I apply a filter as below:

Only 'Laptop A' has any duplicates, and should be the only rows that remain highlighted. Essentially the NameDistinctCount column needs to update with the filters, which I believe is achieved with a measure?