This is actually fairly common with vacuum filler pens (including popular vac fillers like the Pilot 823 and Twsbi 700). Many consider this a feature, as by separating the section there is a lowered chance of leaking when travelling (especially flying) or knocking the pen. While I have no experience with the PenBBS 456 specifically, most vac fillers leave plenty of ink in the section for a few minutes of note taking (Goulet Pens got an 823 to write for almost 10 minutes from just the section) so you don't actually need to unscrew the back every time you want to take a quick note.
This is why I keep the same ink colours or shades in my vacuum filler pens. They either always have dark blue or blue black ink in them.
Smart move!
This works for me with vacuum fillers: First pump in the ink, keep the pen in the ink, and pump it again. Two pumps in the ink, fills the pen nicely.
Sounds like a much better method.
filling starts 8:19
So basically the end cap is always unscrewed when writing. Kinda odd.
This is actually fairly common with vacuum filler pens (including popular vac fillers like the Pilot 823 and Twsbi 700). Many consider this a feature, as by separating the section there is a lowered chance of leaking when travelling (especially flying) or knocking the pen.
While I have no experience with the PenBBS 456 specifically, most vac fillers leave plenty of ink in the section for a few minutes of note taking (Goulet Pens got an 823 to write for almost 10 minutes from just the section) so you don't actually need to unscrew the back every time you want to take a quick note.