Webmaster - Links to your site: No data available

It came to my attention recently that one of my sites no longer has backlinks showing up in GWT. Its been almost a month now since my backlinks disappeared, but I'm at at loss as to why. The site is over a year old, and before a month ago it had around 5 backlinks from other sites in my network. All of the sites are "clean" with a spam score less than 2. I have other sites that are also linked similarly, with their links showing up.

Has this happened to anyone else before? Can I expect them to show up again?

Answering my own question here:

I switched over to HTTPS several months ago, but many links were still indexed as http:// which is why it was still showing results, but nothing compared to my actual traffic.

Just added HTTPS to webmasters, so hopefully I can see some real data for the first time in months.