Did you ask this guy for advice or was this unsolicited feedback?
I wouldn't call it excessive and it's certainly not something I would stop a set for. There are a few things you can do to address your squat in general.
First, you don't seem to be taking a big breath and bracing before each rep. See any information on the site about the Valsalva and then do that to keep the back from wiggling around.
Second, lean over a bit sooner than you think you need to. The shift back may be partly because you're coming down forward of midfoot and the body is getting itself back over it's COB.
Lastly, keep your knees pinned out as you ascend. Shove them out on the way down and keep them shoved out on the way up. That will help to anchor the back angle and keep the hips from potentially shooting back.
Good luck.