Regarding the Hint bugs, here's a screenshot showing what it shows (after doing everything currently in the build I believe).
As for the workbench hints:
- Optical Sensor says to talk to Sarah, but I can't remember who she is or know where to find her.
- Steam Core Details - I suspect we'll need the key to the door in the warehouse, but Secretary only has option to ask about the Master.
I'd suggest maybe adding more important characters to the "Character" menu option, such as The Master, Sarah, Karl, and anyone else who you end up having some kind of relationship with. Including details of name, general location, etc would be helpful as well.