according to Damyon (from previous chats) the cron should have carried on and recorded in its pages that something failed.. this is when DB conn failed btw.. a real exception :-D

Database transaction aborted automatically in core\task\legacy_plugin_cron_task
Default exception handler: Error reading from database Debug: MySQL server has gone away
SELECT * FROM task_scheduled WHERE classname = ?
[array (
0 => '\\core\\task
legacy_plugin_cron_task',
)]
Error code: dmlreadexception

• line 443 of /lib/dml/moodle_database.php: dml_read_exception thrown
• line 1014 of /lib/dml/mysqli_native_moodle_database.php: call to moodle_database->query_end()
• line 1476 of /lib/dml/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()
• line 1448 of /lib/dml/moodle_database.php: call to moodle_database->get_record_sql()
• line 1427 of /lib/dml/moodle_database.php: call to moodle_database->get_record_select()
• line 562 of /lib/classes/task/manager.php: call to moodle_database->get_record()
• line 90 of /lib/cronlib.php: call to core\task\manager::scheduled_task_failed()
• line 61 of /admin/cli/cron.php: call to cron_run()

PHP Fatal error: Uncaught exception 'coding_exception' with message 'Coding error detected, it must be fixed by a programmer: \core\lock\lock() has fallen out of scope without being released.
Locks must ALWAYS be released by calling $mylock->release().' in /var/www/vhosts/moodle.org/html/lib/classes/lock/lock.php:107
Stack trace:
#0 [internal function]: core\lock\lock->__destruct()
#1

thrown in /var/www/vhosts/moodle.org/html/lib/classes/lock/lock.php on line 107

*note not necessarily needs fixing but this is a good record to have re new cron management in 2.7.
ping damyon - in case there is any possible developments here.