When I received my green V3Pro (most recent version, I believe) it had a spare screen in the box, with the cut-off segment, I wondered why it was there, and why it would have a flat cut off of it, when the chamber is round...
My OG black one did not come with that spare in the box. I think XMAX added them to answer customer concerns, issues like op
@cardyology was describing.
Just now, for the very first time, I realized the green one has had one of these "top screens" inside all along.
So, for that one, this set for sale would be a replacement.
Looking at the OG, no mesh screen down there at all!