I read on one of the forums that a guy who tried M77 reported that it separated with heat. He used it anyway and said it didn't stay on the splines and he saw wear later.
The use of M77 is widely reported with satisfaction. It is fair to say that in some cases, thorough cleaning of the splines is neglected and
that would cause adhesion failure. A thin film of paste carefully applied to a clean surface is all that is needed.