I had approved the preg question type - https://moodle.org/plugins/view.php?plugin=qtype_preg and received the following:

Error: AMOS threw exception mlang_parser_exception: Error: Expected character ; at line 190

Line 190 contains:

$string['too_large_fa'] = 'Regular expression is too complex to be matched by {$a->engine} due to the time and/or memory limits. Please try another matching engine, ask your administrator to <a href="'.$CFG->wwwroot.'/admin/settings.php?section=qtypesettingpreg"> increase time and memory limits</a> or simplify you regular expression.';

I suspect concatenating the string caused the error since it reached the closing single quote and did not see a semicolon. I am going to recommend that the string be changed to use the $a variable to pass in the link. When a new version is uploaded, will it be re-parsed?

Peace - Anthony
Peace - Anthony