Region envelops not working properly

Using latest 2.4 SVN (version 3463).
Something is screwy with region envelops : if you happen to have edited a few of them a bit heavily, you get severe master volume dropouts that can last a few seconds when playing the whole session. The volume dropout occurs when the transport reaches the edited envelop. When you solo the tracks containing the edited regions, you don’t have this problem. It is noticeable when you play other tracks along at the same time.

Update: the weird thing is that I just had to move around one edit point by a few milliseconds and things went back to normal. So I suspect the envelop was corrupted but its display did not reflect the corruption. But considering the symptom, it seems more tricky than that since it affected the whole master volume, with a volume dropout of a couple of seconds.

Well, actually, the display is also screwed up. I had already submitted a bug report concerning weird envelop display. Does it have to do with the sound dropout I noticed lately ? I don’t think so because it’s the 1st time I hear the problem whereas corrupted envelop display has been there in many prior versions :