Mass produces gravity and is subject to it. It seems impossible to separate the two phenomena and the equivalence of the two forces was stated centuries ago.
Wiki considers measuring two different gravitational masses - active and passive. It also states that:
Although some theorists have speculated that some of these phenomena could be independent of each other.
So did physicists actually ever consider the possibility of different values for active and passive gravitational masses? If so, why might have they expected them to be different and caused by independent phenomena?