One way would be using Conditional formatting
If you plan to always enter your reference date in D59 try the following :
Select the range containing tour dates to check (say D150) - go to Conditional Formatting - Use a formula
As formula enter and choose the format you want when the condition is true The formatting of the duplicate will then change in your range

If the dates in range D150 are not true dates, let us know so w can help further

There are also other possibilities

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