The patch deploy just went out, so you should be able to refresh the Designer (or Editor) and get back to editing your text! 
Our sincere apologies for this annoying issue!
@rayjnorris We deploy fixes/changes/improvements many times a day (sometimes multiple times an hour), and this issue unfortunately cropped up due to a (theoretically) unrelated change in the Style Tab that inadvertently touched some text editing code - which was unfortunately not caught in QA in this case, since the test spec was targeted at Style Tab workflows.
While we have thousands of unit/component tests that must pass before builds go out to production, but despite that this particular issue wasn’t caught by those tests. To fix that, we’re working on adding a suite of Selenium-based regression tests that run through common actions in the actual Webflow UI across multiple real browsers. This should make these kinds of issues much less likely to slip through the cracks.