Badge images on the "Issued Badge Information" page (badge.php) are incorrectly stamped with the "EXPIRED" overlay image. When the user hovers over the image, the following tool-tip appears: "This Badge Expired on Thursday 1 January 1970." (ref. attached image).
The unix timestamp values in the table 'course_completions' are correct based on the actual course enrolment, start and completion dates. I would suggest whatever logic is used to display the EXPIRED overlay stamp is failing to convert the unix timestamp (which is why we are left with a reference to 1970).
The very same badge thumbnail appears [correctly] via mybadges.php (Manage Badges) without the 'EXPIRED' overlay image (ref. attached image).