Has anyone else been experiencing track stack summing issues? Here's what happens to me: I have all my drum collected into a "summing" Track Stack. everything is fine for a while until I get further into the track. And then suddenly for no reason, all the outputs from the individual drum stems revert back to the main outputs. they are still in the track stack as it were but they have completely bypassed the summed output. Does anybody have an idea as to why this happens? Many thanks in advance.