I have observed dupes traveling through transit tubes will break a room's vacuum in the following cases:
- Carrying an off-gas material such as oxylite or slime.
- Wearing a soiled suit (dupe pee'd in their suit).
The expectation is that travel through a tube shouldn't destroy a vacuum. Since a transit tube crossing protects a vacuum, the tube connected to it should as well.
Steps to Reproduce
Build a transit tube through a room that maintains a vacuum. Send a dupe with an off-gas material or a dirty suit through the room. It may take multiple trips for the off-gas to occur within the room, but at some point it will happen.
This issue has not been confirmed by a developer yet.