Trying to highlight consecutive duplicates

[marvrulz]

Hello. I have a workbook in which I want to highlight consecutive duplicate values within a specific column. Using the canned conditional format option for highlighting duplicates highlights all values that appear in the column more than once and I only want duplicates that are consecutively listed highlighted. I found many websites that say setting a CF rule using the formula =or($A1=$a2,$A2=$A3) would work and many even show screenshots of it working. For me it does not work. Using that logically results in the cell just prior to a group of duplicates getting highlighted and the last cell in a each group of duplicates not getting highlighted. It also highlights the last cell which I do not fully understand. It highlights blank cells at the end which I can clear up with another CF rule once I get the primary one worked out.

Please help as I feel like this approach is only not working for me, but it makes sense to my why it is not working. I am also open to a completely different approach, ideally one that I can apply through a CF.

I have attached a basic example of of what the current result is and what I would like the result to be.

Thanks