Here’s some additional information…
I just noticed that the BadgeOS points are not being logged for users who complete quizzes. It seems to still be logging logins. Based on the BadgeOS log, the last badgeos_leardash_quiz action was completed on 05/09/2017. I can’t see anything out of the ordinary that would have affected this. I don’t have any “last updates” to a plugin on this date or on the 10th. There was a wordpress on May 16. The nearest site change I can see was an update to LearnDash LMS on 2017-05-11.
However my logs only show the most-recent updates to plugins so the following plugins may have had an update on or around this date, but have also been updated since then.
AffiliateWP
Invisible reCaptcha
Pretty Link
SEO by SQUIRRLY (currently deactivated)
WooCommerce
Wordfence Security