Having problems to model that case with DDD

I’d like to as for some guideline or hint how to model the following problem with DDD.

I need to calculate loyalty points based on some defined Policy and Order placed. I have following model:

aggregate Policy {

Id;

Name;

Strategy; // Entity

}

entity Strategy {

Id;

PointsPerOneUsdSpent;

OtherImportantProps;

}

… and now I want to keep track of all issued/calculated points:

aggregate ProcessedOrder {

OrderId;

PointsGiven;

StrategyUsed; // this is problematic

}

if I keep StrategyUsed [frp[erty as a reference to Strategy entity object, I will reference same entity from 2 difference aggregates, which is wrong. How to tackle this problem? Should Policy/Strategy and ProcessedOrder belong to 2 different bounded contexts? Or maybe the Strategy should be a value object? Or is there simpler way?