It looks like the apostrophe character breaks the display.

To reproduce:

1- Create database activity
2- Add a field with an apostrophe (') in the field name
3- Add an entry
4- Check the result

 On Moodle 4.1.8, it wiil display the template entry insted of the actual entry.

[[Test d'apostrophe 1]]

I also checked on qa.moodledemo.net (running 4.3) and I get a slightly different behaviour: the entry is duplicated.