Reported by licensee: [Link Removed]
In UE4, we used Multiply_Vector2DFloat as the underlying function for this operation. In UE5, we're relying on promotable operators to the work. However, that only works if we have a corresponding cast function. In this case, we're missing a Conv_FloatToVector2D function in KismetMathLibrary, which prevents multiplication in this case.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-150441 in the post.