Safety question on wood stove insert

Hi,

I was cleaning the liner today with a soot eater from the bottom, and after I was done, I decided to look up the liner. Not an easy thing to do since I have an insert, but was just curious how it looked. When the liner was installed it was a little short (I'm guessing) so they did the final connection with stove pipe. They used a 90deg at the bottom, but it is mostly just going straight up. Anyway, it looks like one of the rings (or at least that is what I'll call it) has separated from the next one. This is real hard to explain since I don't know the terminology. Anyway, it looks like it separated a bit from the next ring. I'm not certain about this, but if this did happen, is this a safety issue? The chimney is between the house and the garage and I have CO monitors in both rooms (1st floor and 2nd floor) where the chimney touches. Also, I wonder if this is separated, was it likely done when the insert was installed?

Thanks!

Be green,

Yes, that's it exactly. I'll have to take a picture and post it here. I'll also bring it to the shop that did them work.

Thanks for confirming my thoughts.

The 90 is not stainless. I seem to recall it was just black stove pipe. I would take a picture now, but it is about 500-600 degrees in there. I think it is supposed to warm up this week. I'll take a picture the next time the stove is cold.

Thanks for all of the input. I have not been to the installer yet but will and now I have some good questions for them. Keep any recommendations coming.