That is not one of the markings that Titleist has had on a Pro V1.
It may be that the balls you found were possibly "refinished" and whoever did that work also added that identification marking.

That’s interesting for sure.

yes have seen it a few times but on balls i have found and not bought.

Not a ball that is currently offered. Also did a little research and found a Titleist post that shows the marking of Prov1s from 2000 thru 2019 and none match what you have. Dale, Chris, Todd. You guys have any idea. Might be a tour ball? Do not know if they mark them differently? Just an uneducated guess.

www.titleist.com/.../how-to-tell-which-year-your-titleist-golf-ball-is-from

Just announced this morning on this site.

NOW ON TOUR: Next Generation Pro V1 and Pro V1x!

It's the newest ProV1

Lucky find! Looks like the new 2023 ProV1 that is rolling out in your this week.

Yep, Titleist just released a picture of a hand holding both the ProV1 and ProV1x. They show this new alignment marking. In the mean time, test balls are marked as "protos" but are basically the same ball.