1. Add a Questionnaire to a course.
2. Add Recent activities block to the course, click on "Full report on recent activity"
3. The search throws the error:
   "Exception - Class 'questionnaire' not found"

With developer dbugging turned on, the messages are:

Exception - Class 'questionnaire' not found

More information about this error
Debug info:
Error code: generalexceptionmessage
Stack trace:

line 772 of \mod\questionnaire\lib.php: Error thrown
line 167 of \course\recent.php: call to questionnaire_get_recent_mod_activity()

Tested Moodle 3.5.2 stable and 3.5.3 stable using Boost, so far.