Upper management tracks notes about every individual, especially if the notes are about certain topics of interest at the time.
When you talk to your manager, they take notes about what you say. Even in other meetings besides your 1:1, they'll note what you say if it's about certain topics.
Your manager's manager occasionally asks about each individual and takes their own notes. The reason they're taking notes again is that lower level managers don't know about the secret tracking system. Turnover is too high at the lower level to rely on them to always keep it a secret.
All of your complaints, even if casual or joking, are logged. General notes about your productivity and engagement also go in there. This information is used for annual ratings, comp, and layoffs.
Be careful what you say, no matter the setting (office, Skype, etc.). Extend only minimal (if any) trust to your reporting chain.
Who among you will confirm the above?