Familiars may be sucked into PneumaticCraft Vacuum Traps and subsequently duped.

I haven't actually duped them to see what would happen, and I intend to blacklist them in e6, but I thought I'd let you know you can fix this by default simply enough by tagging them as Tamed creatures.

Any tamed pet is automatically excluded from the vacuum trap.

Is there a tag like a json file to add? Or are you saying just tamed creatures in general

Just tamed creatures in general are excluded. Like you can suck up a wolf, but not a tamed dog.