Conditional Formatting Rules Change when Inserting, Deleting [finding duplicates]

Hi all,

Sorry if this is in the wrong place, but I think it fits here as it's a function. I tried the search on all forums but couldn't easily find an answer to my dilemma.

I have a sheet where I'm searching for duplicate values in Column A. My conditional formatting rule is as follows:
Example1.png

However, if I ever insert, copy or delete rows, the "Applies to" data changes, example here:
Example2.png

This causes some rows to be excluded from the function somehow.

This is an ongoing spreadsheet I use at work and make weekly edits to. Is there a way I can have it so it will always look for duplicates in the whole column no matter what? (I want the $A:$A to always be the case no matter what happens to the sheet)

Thanks in advance!!

Got it, thanks!!