SONARJAVA-2795 removed FP when the call is ambiguous and can not be replaced by a lambda.
It uses a heuristic to identify if a method can be ambiguous:
suitable method is instance method with no parameters, or static method with single parameter of the same type as lambda argument
The last part is not precise enough, the lambda argument type can also be a subtype. If it is the case, the rule will still report FP.