Env:
PHP 8.1
Moodle 4.2 (integration master)

1. Go to question bank
2. Create a question
3. Now, back on the question bank list, click 'duplicate' from the question options
4. There is an error on the page (under the header, so hide it with css to see it)
5. Save the duplicate and observe the same error:

 Deprecated: preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated in /home/jake/moodledata/imaster/moodle/lib/questionlib.php on line 1985