I am creating a custom extension that retrieves item information on the PDP (Product Detail Page), formats the price, calculates the savings price, and displays it. I am using addToViewContextDefinition for this, which sends it to "ProductView.Price.View". This price is being shown on both the PDP and related items. When I click on a related item, the page doesn't change, and the console shows this error: "Exception on event handler for event beforeShowContent DUPLICATED_CONTEXT_PROPERTY: Duplicated propertyName. Trying to add more than one extra context property with the same name." Any help would be appreciated!

Just like another person has found out, it sounds like you're modifying the view class using a beforeShowContent event which means that it's trying to add this property every time you visit a PDP

I am using PDP component something like this PDP.on("beforeshowcontent",funtion (){ //my logic here layout.adddChildView() }

Yeah, so don't do that

So what should be the best alternate to achieve this ?

Don't wrap it in a beforeShowContent event listener