This applies to all custom fields, including scoring metrics.
When creating a report using features, the list of custom fields and scoring metrics spans all products even if my report is filtered for one specific product. This makes it very confusing to know what I am supposed to select.
Product 1 has a scorecard with metrics Sales increase, Marketing impact
Product 2 has scorecard with metrics Sales increase, Marketing impact, Effort
The available score fields in reports shows sales increase twice, marketing impact twice since they exist in two different scorecards.
When a filter for a specific product is applied, only custom fields available through that product should be selectable.
An alternative solution that may be an easier quick fix would be to at least show the product prefix in front of the field name. Of course, this could be a display issue when you have one field used by many products.