In an X post Tuesday, the NYC tech CEO -- who appeared on the couple's Netflix doc as a talking head -- says the video of the Princess of Wales at the Windsor farm shop last weekend definitely doesn't look like the real Kate, in his eyes anyway.

In fact, in another tweet of is -- he goes so far as to claim that the woman seen walking in our clip might actually be a stunt double. He also posted a mash-up of videos showing her walking with Prince William in the past to back up his theory.

Chris wrote, "I've compiled a few older videos of William and Kate walking together, as well as the recent video from Windsor Farm. Take a look and decide for yourself if it's Kate or not. In my opinion, we still haven't seen Kate in public."

There's more ... a quick scroll through CB's X page shows that he seems pretty fixated on his theory that the recent Kate sighting was a doppelgänger situation -- totally leaning into it.

He's also tried analyzing footage of Kate strutting in heels versus flat shoes ... saying based on the strides he can see from old clips, he seems sure Kate wasn't at the Windsor Farm Shop last weekend.

As you know, everyone's been speculating about Kate whereabouts since she hadn't been seen since she was hospitalized back in January for an abdominal surgery.

She was off the radar for so long that folks started tossing around all sorts of theories about where the Princess could be ... and a lot of wild suggestions have been floated.

Things really hit the fan when she was spotted in Windsor -- as seen in our excusive video -- but Bouzy's among those who isn't buying the footage, saying the way Kate was moving so briskly while holding a bag ain't in line with someone advised to take it easy after surgery.

FYI ... Bouzy's no stranger to throwing shade at Kate and Will, having previously tweeted they were aging in "banana years." In comparison, he's always had Harry and Meg's backs ... defending them from the trolls, saying they shouldn't have to deal with that nonsense.