When I click "Show hosts" on any project, it only shows me one of dozens of my computers however I know that more machines run a project, I checked that. Is it a bug?

What page are you looking at?

BAM! :: Hosts per project

https://boincstats.com/en/bam/projectHosts/0/

I see only one laptop in the table but I know and can see it that several more computers are running this project at the same time.

I think I got it. My laptop is not assigned to any group. So this page shows hosts that are not assigned to a group and all groups. Am i right?

All I see for myself is one project: SETI and I see all my hosts. However, I'm not using groups because there's still a bug present (last I knew) that screws up what's connected and not connected so I can't see if hosts in groups show or not...