Email is sent at strange times for bugs with dependencies that are voted on. The problem is that a vote does not cause email to be sent, but it does add the voter to the cc: list (explicitly in the text used for email diffs, but not in the bugzilla form). However, if a dependency of the voted bug is modified, the text for the voted bug is rebuilt to see if email should be sent. Since the text has changed, this causes email to be sent listing the voter as added to the cc: list. That is, when I voted for bug 10593 and then commented on bug 11992, the change to bug 11992 caused mail to be sent for both bugs. The only way I see to get around this would not be to list the voters explicitly anywhere in the text file used for comparisons and email diffs.
Yes, this is certainly a problem. I think, although can't prove, that I've been added to a cc list I was on a second time because of this.
Yes, you diagnosed the problem exactly. I think I have finally fixed it. The email stuff is just too disgusting a hack...
per Terry, auto-verifying any resolved bug that hasn't been touched since before 2.10 was released.
Moving to Bugzilla product