Not a bug "Display unviewed media counter" does not work properly

[Kirby]

Affected version

2.1.2

Steps to reproduce

1. Login with a user account A and note down the counter
2. Upload a new media with another account B
3. Check the counter with account A

Expected Result
The counter has increased by one

Actual Result
The counter has not increased.

 

[Chris D]

The counts are cached for 5 minutes.

 

[Kirby]

This is not what a user does expect.
If you want to keep this behaviour (which does make sense in regards of performance) this should be documented.