Wrong Message - End of Sharing

i have NC latest Version on Debian Jessie PHP 7.1 with Apache installed. I share one Folder with Password an no endtime for sharing. After 5 days of sharing i got an email with notification of “Öffentlicher Link für xxxx ist abgelaufen / Public Link for xxx has ended”. I got still access to the link. So the question is, what does this mean, while i have not setup any livetime of the link? thx