I believe you make reference to the Merchandising eVar using product syntax: https://experienceleague.adobe.com/docs/analytics/components/dimensions/evar-merchandising.html?lang=en
// This merchandising eVar uses conversion variable syntax, and counts an instance.
// However, if the binding event and products variable are not both set, the instance attributes to "None".
s.eVar1 = "Tower defense";
// This merchandising eVar uses product syntax, and does not count an instance.
s.products = "Games;Wizard tower;;;;eVar2=Tower defense";
So based on this you need to make sure to avoid any character that are used in the s.products syntax:
avoid:
- ; as it delimits the product sections (product catefory;product sku;)
- , as it delimits each product description
- | as it delimits multiple value for some placeholders
- Events (optional): Events tied to the product. Delimit multiple events with a pipe (|). See events for more information.
- eVars (optional): Merchandising eVars tied to the product. Delimit multiple merchandising eVars with a pipe (|). See merchandising eVars for more information.
If you are using conversion variable syntax this does not really matter