Bulk edit availability modal does not translate to current language

If you enable bulk edit and click the availability link, in the opening modal not all strings are translated.

Steps to recreate

1. Go to qa.moodledemo.net, to the "Activity examples course".
2. Change the language e.g. to German.
3. Activate bulk editing ("Massenbearbeitung").
4. In the footer overlay, select the translated string for "Availability".

WHAT YOU EXPECT
The strings in the modal are translated.
WHAT ACTUALLY HAPPENS
Not all strings in the modal are translated.