Probably not a bug, but I hope this answer can help you narrowing down your issue.
First of all, one needs to understand what is a 'day' in Stack Exchange and realize that badges like Enthusiast and Fanatic are awarded based on it. See:
What is an SE "day"? When does each day start?
Basically, a day starts at 0 hour from UTC time. Then, one can check which days the system counted as visited (remembering that just logging in does not count):
Just go to the user tab profile and click on link
visited x days, y consecutive to see if any 'day' was missed. For example, I missed day 15th in March, here in CV Meta :(.
If it is the case you haven't missed any day, and this is indeed a bug, I suggest you to post a question in the main Meta Stack Exchange site. Link to this question there for providing some introduction.