I have exactly the same problem.
Ubuntu 16.04, php7.2, mysql
5.7, Moodle 3.7.1+ (Build: 20190824)
Forum posts are getting send out until I delete them.
mdl_notifications gets filled up with a line for every repost of the forum message.
In mdl_forum_post is marked as mailed (mailed = 1)
In the logs I only see it been send once, without an error message (see log at the bottom of my post
Due to the holidays, the server
has not been used for two months. I have upgraded from 3.6 latest to the current latest version and it started happening with the first post made on the server (the second and the tirth show the same problem). Changes are the upgrade of Moodle, upgrade of the php version (7.0 to 7.2) and adding of the tool https://moodle.org/plugins/tool_cohortdatabase
I noticed https://tracker.moodle.org/browse/MDL-65888
, but I can't find any error messages in Moodle logs.
(Execute scheduled task: Forum-mails en onderhoudstaken (mod_forum\task\cron_task)
... started 21:30:04. Current memory use 31.4MB.
Removing old digest records from 7 days ago.
Removed all old digest records.
Fetching unmailed posts.
Processing post information
Processed 1 posts
Filling course cache
Filling forum cache
Filling discussion cache
Filling user subscription cache
Filling digest cache
All caches filled
Queueing user tasks.
Processing 1 users
Queued 0 digests and 1 messages for 2
Queued 0 digests, and 1 individual tasks for 1 post mails. Unique users: 1 (0 ignored)
All tasks queued.
... used 15 dbqueries
... used 0.037278890609741 seconds
Scheduled task complete: Forum-mails en onderhoudstaken (mod_forum\task\cron_task)