Behaviour:

1. go to job configuration
2. enable "Restrict where this project can be run"
3. enter expression with operator, e.g. "label1&&label2"
4. go to slave that is configured to run label1 and label2
5. klick on label1 (link next to "Labels:")
6. URL $your_jenkins/label/label1/? will open
7. Project using "label1&&label2" won't be displayed, only projects that use "label1" and nothing else will be displayed

Workaround: enter $your_jenkins/label/label1&&label2/ as URL

Expected behaviour:

Klicking on a label (i.e. navigating to $your_jenkins/label/label1/?) should display all jobs that actually make use of this label regardless of using it alone or in combination with other labels (via an operator).