anyone else had this problem?
http://youtu.be/Q64aBM-zGU0
Before I go on, I should mention it would be helpful to put a written description in your OP. The video is a bit confusing/scattered.
Anyway, I believe I have a similar problem. Whenever I use Siri, my alert sounds go to full volume. For instance, I typically will lock the phone out of habit, and the "click" will knock you over. I can clear the problem by tapping on the alert sound slider in Settings > General > Sound. I have the option to "change with buttons" off, though it doesn't seem to make a difference.
There's at least one other situation that triggers the problem, but I can't remember what it was - if I get it to repeat, I'll post back.
The Siri related problem is very repeatable, though.