The Standard Features user role has Can forward private messages set to No. 

The Limited Features user role should have the same, but in a default installation it gets set to Yes. 

This also impacts the No Avatar use role, which have a limited feature set and has Can forward private messages set to Yes. 

This impacts admins who might create other limited feature set roles using settings from the Limited Features and therefore will inadvertently give users assigned the role the ability to forward private messages.