From whither, smoke?

I've got a brand new morso badger stove with excel double-walled pipe and I'm getting a whiff of smoke coming out somewhere when it's well burned down and/or smoldering. Not enough to kill me, so far, but a bit annoying.
As far as I can tell, the only possiblities for a leaky spot are the stove itself somewhere (intake I suppose) or the connection of my stovepipe and the collar on the stove.
The stovepipe is corrugated where it sits over the collar (the piece they gave me to connect was bizarre and useless, so this is all I could do) and it sits 3/4" or a bit more over the collar. It's pretty snug, but I wonder if the corrugation might be letting the smoke out a bit when the draft is weak. I can't recall if there was the 2nd wall of the pipe came down as far as the collar or not. Can't open it now to see, it's blazing.
I do have double walled all the way, and it's 15 feet of pipe, so draft is excellent in general.
I guess I could try filling it in with hi temp cement, but I want to get some opinions before making that mess.

Or have you ever known a stove to leak backwards from its intake under a weak draft/smoldering condition?

Thanks for any insight.

Sorry this pic is so huge!

I looked hard at it both ways, don't think it fit any better upside down and the vague manual seemed to show the extendable overlap going the way I have it.

So I finally found the leaky spots. Everywhere. Had a sputtering ignition at dawn and my flashlight showed smoke kicking out of the back of the stove briefly, but mostly through the pipe where it meets the stove's collar and where it connects to my ceiling box. These joints felt fairly snug, but obviously they're not.
Can I call ICC and make them buy this crap back off me?
How hot does stovepipe get - can I use 500 degree silicone on the joints?
I'm really pissed off that this ultra pricey pipe is such crap. Making a tight fitting joint would seem to be about the #1 priority when building this stuff.
Thanks

PS which way should a telescoping section fit anyway? It seems logical that you'd want the smoke to slow up the first section - male joint into female above, but I read someone saying it's opposite, so any water will run down into the stove, not onto the stove top. I've tried both ways, in case that was my leaky spot. It's not.

PSS that corrugated has a smooth 2nd layer behind it - I took it apart to see - so the corrugations aren't leaking, though the smooth one still is.

I'm still finishing the house up, just a tiny one-room cabin, and there are a pair of little holes by my door - didn't get sealed up yet. But I'll try cracking a window next time just to double check that. It is pretty tight otherwise, maybe those small holes aren't enough. That does make sense as a possibility. Small house size would amplify that effect too, for sure - less air to "stretch".