The only ones knowing you were visiting the bank's website were you and, well, the bank.
So, assuming the bank hasn't been hacked and the HTTPS communication can be trusted, what other information might have leaked?
- DNS query. When you connect to www.securesite.baz, a DNS query goes out (in the clear) and can be sniffed - for example - by your WiFi router. There have been instances in the past of routers that had been hacked, not so much as to be blatant, but enough to grass on their users' movements back to their command-and-control network. The next step is trying to hijack the DNS query altogether, but that's doomed to fail with all the new security measures in browsers against MitM attacks.
Do these occurrences happen only when you browse from a specific network (your home network, your phone's mobile data network, ...?).
- resource URI snooping. Some browser extensions can request read access to the URI of network requests for "safe" media types - but if I see "https://www.securesite.baz/static/img/logo.png", that also tells me you've been visiting securesite.baz.
Does this happen with every browser? Consider disabling all extensions or researching them on the Internet.
- indirect URI snooping. Most "invisible" malware hasn't enough access power to read your network calls, much less SSL system calls. But the browser caches a lot of information in known places that are accessible at the user level - both Firefox and Chrome keep much of that in a convenient SQLite format - so I can get some inkling of where you're navigating with you being none the wiser.
Can you try navigating with a new and trusted device from the same insecure network and see whether this elicits a phishing run or not?
One way of investigating might be trolling for bank sites. Run a search on all nearby banks and visit all their sites. Most low-access, light-fingered malwares won't be able to tell between a visit to the bank's privacy policy page and the opening of a juicy account. You can note down which sites you visited, how, when, and with which browser, and then see what comes out of the mailbox.