Question regarding Simpson Dura-Vent

[Sono]

I installed my pellet stove and works great, ran for hours and no CO detectors went off, and checking them still had no readings, all at 000ppm
I noticed the last 2 start ups I got a little whiff of smoke but nothing after start up and CO detectors remained at 000.
Last night I went out and at start up I used a flashlight to check the pipes and stove connections and all was great and then I found it, right in the seam of the "T" where the inlet from the stove goes into it a tiny stream of smoke pulls from it back towards the stove.... once it fires the smoke stops and no more smell. Im not sure if this is normal or a concern? I was thinking to just seal the area with sealant or is there more to it? This is coming from the outer pipe thats spot welded on the T itself.

 

[ARC]

Some red or orange RTV high temperature silicone you can get it at most hardware stores or automotive parts store.

 

[Sono]

Some red or orange RTV high temperature silicone you can get it at most hardware stores or automotive parts store.
View attachment 344076

That is what I was going to do, Just wanted to get advice if it was safe. Surprisingly even with the CO alarm next to it, nothing is detected as Ive moved in around the shop thoughout the night over an 8 hour period and nothing registered... I just installed a wired CO detector thats permanent in the shop that doesnt rely on batteries.