Many people are reporting weird text display problems with various apps in macOS 14.3, most notably Apple’s Mail, Notes, and Safari, but also third-party apps that rely on WebKit, including Mimestream and MarsEdit. Words or entire lines will seem to disappear and reappear, jump around, or overwrite other text.
Although the problem is disconcerting, it’s only cosmetic—the actual text isn’t changing. Any action that causes the window to be redrawn—resizing, switching to another window and back, closing and reopening—will likely return the affected text to its correct state.
I’ve learned that the bug has been fixed in WebKit, so it’s just a matter of Apple integrating the fix into an update to Sonoma. I don’t know whether that will be macOS 14.3.1 or macOS 14.4, or when it will appear, but it shouldn’t be long. The release schedule may also depend on Apple’s need to address newly discovered vulnerabilities in an upcoming security update. Regardless, sit tight, and we’ll have a fix soon.