Detected by isabelrenedo in the Moodle App, I'm opening it in Open Source project to investigate it.
What she did is:
- Access a course in the app and leave (so the data is cached).
- In LMS, add a new activity in the course (a URL resource).
- In the app, download the course.
- Go offline and open the course. The new activity's title isn't rendered, it displays the grey area that is displayed while the filters are being processed.