Strange Object on Night Vision

I’m not saying “it’s aliens” so don’t jump on me. I wanted to post here with open-minded people, in addition to r/stargazing for more standard explanations. Obviously y’all deal with the weird and anomalous so hopefully some big brain on here can chime in and help me out with something I saw last night. Hopefully the debunkers who have a great explanation for everything have a great explanation for me that I can research and learn about.

I am a lifelong stargazer here who has logged many hours on the telescope, binoculars and naked eye. Recently I added a pair of gen 3 night vision goggles to my arsenal of observational tools. They open up the visibility for satellites, stars, shooting stars etc way way more than you can see normally. What I use is a 1x lens so I have broad visibility and then I can use the telescope or the binoculars to zoom in on specific spots if I want to.

I saw a weird one last night on the goggles. It was the first hour after sunset which, as you know, is the best for picking up satellites etc. Anything moving around the atmosphere will be illuminated by the Sun just behind the horizon which makes for excellent optics.

That said there was flashing coming exactly every 18 seconds from a fixed position in the sky. It did not move in between flashes, it was undetectable to the goggles between flashes. The flashes could not be seen with the naked eye. That means it was not reflecting any light despite every other satellite being lit up like a Roman candle. These goggles see everything, so why was this object not reflecting light like everything else?

And whatever it was doing was happening at regular intervals and it was fully stuck in space. I can’t imagine a star that is “off” 17 out of 18 seconds at a time. My other thought was it could be a piece of space junk continuously rotating and catching the Sun or a satellite in geosynchronous orbit, but the reflection from the sun should keep it visible the entire time to the NVGs. And I would imagine space junk drifts instead of being absolutely fixed in space. I have no explanation for what I saw. Thoughts?

I know a few aerospace engineers I’ve asked about this and they are thinking on it. I was wondering if any hobbyists with big brains want to chime in. I’ve never encountered anything like this before and would like some input from rational minds.