Staggered Tooth Side Milling Cutters

[J Tiers]

Yes, that is probably the issue. The deeper you go, the faster it gets to a multi-tooth cut, which is super-smooth. Also the deeper you are going, the less you are "on the corner", so as the tool approaches the edge is "coming up the side of the part" more than hitting the corner. When approaching on a shallower cut, you have to be into the part quite a way before the next tooth starts cutting along with the one before it.

Your H-mill is bigger, also, so what slams on mine is just a gentle bumping noise on yours!