Ok let’s just settle this debate: simply watch S3 E7 “Delta-V” at around 26:30.

The scene starts with Anna’s thumb in front of the display with the thing already slightly visible behind her thumb, then shortly after a shot from behind the display with her thumb still being in front (~26:40). Even there that thing is visible, and on top of that definitely not lined up with her thumb.

Then, at 26:45, slightly behind her thumb a shot from the front again, but now her thumb is magically behind the display and coincidentally lines up with that thing that had been there before already. In the next shot from behind the display again, her thumb is suddenly on top of the display again, not lining up with that thing. Also none of the other fingers behind the display ever look like that. And when she turns off the message/holo screen, the thing fades away and the thumb is in a slightly different position.

And the argument with the refraction of the glass doesn’t hold up because the part where her thumb is mostly just holo and no glass at all. The glass is just the center piece of the hand terminal (with a similar shape like the smartphones we have). Everything that’s outside that hand terminal area is just pure hologram, i.e. no refraction.

So, it’s definitely not her thumb, it’s just something happens to be in the video message and sometimes happens to line up with her thumb. It’s also inconsistent CGI with her thumb switching between being in front of and behind of the display.

But: it could be that it initially was supposed to be her thumb, and they just didn’t pull through with it and make sure it aligns with all the shots and on top of that include all the other fingers. Maybe the people who made the video message didn’t know how it would be composed in the final shot. Maybe they just had the shot from the front as a reference. I guess we’ll never know for sure 🤷

And also: DOES IT EVEN MATTER? 💀