kuroi:
Something was altering your URLs. For example, if you hovered over the Hallowen Masks category the URL behind it ends .html. Zen Cart URLs don't end like that.
Interestingly this stopped happening while I was typing this response, which means that either you turned something off, or you had some corrupt paths in a cache somewhere, which could possibly explain the problem you were having.
Somewhere along the line I went into made all URLs in both config files HTTPS, for both the http and https locations and that solved the problem. One of the config files has that instruction but the other one did not, so I was unsure whether to do so or not. But, since my entire domain is secure, I guess it was appropriate to do so.