Sessions (:session-save) have not been saving properly in v1.14, a known issue related to QT. No news about it in changelog.
I've updated the related issue earlier this week though: https://github.com/qutebrowser/qutebrowser/issues/5359#issue...
FWIW, saving isn't the problem - restoring a tab's back/forward history from the saved file is.
I assumed my problem was related to the QT issue because it started at the same time, but I was wrong. It's just a configuration mistake. I had `session.default_name` set to no value, and because I typically exit qutebrowser with "ZZ" (`:quit --save`), the last session I created was getting overwritten by the contents of my last-viewed windows.
Wouldn't have checked if you hadn't responded. Very grateful.