Have you tried different saddles? Cinches? Saddle pads? Have you tried it without the breastcollar?
I would switch it all up. Try a longer girth, a different saddle and a different pad. Leave the breast collar off. Also, try putting your saddle and cinch back a bit.
Endiku - Yeah he's not going anywhere without me. =) Other than the 2 acre pasture when he retires. ;)
Jwells84 - I spend a good 5-10 minutes slowly cinching him up to avoid the situation. I think it helps but doesn't always stop it. I do have a bareback pad, I'll have to see if he does it for that.
JustDressageIt - It looks normal, but he is pretty much frozen and out of it. Its hard to show it without pushing him over the edge. Its just a snap, he freezes, won't move until I ask him to. Which he goes over backwards or bolts forward. I'm forcing my sister to come with a camera tomorrow. I'll see if he acts like he did today.
Yeah, >_< Its how I used to saddle. I thought I was clever in slowing up the part where I cinched up. I then thought about the mechanics of it and I no longer do the breast collar first. No worries, I understand the dangers and changed the order of how I saddle up.