According to Apple, some of the bug fixes included are for widgets where dragging them around could accidentally remove apps from folders. There are also bug fixes that addresses some issues with the Mail app, the Phone app, along with zoomed display mode, being unable to download or add songs to your library, and so on.
In addition to bug fixes, iOS 14.1 also introduces support for 10-bit HDR video playback on devices like the iPhone 8 and later, and also improves on compatibility with Ubiquiti wireless access points. So if you have been having some issues after the update to iOS 14, hopefully this update will address some of them.
Apple is also working on iOS 14.2 and has already seeded the beta to developers and public beta testers, so if the fix you’ve been hoping for isn’t in iOS 14.1, hopefully it’ll be coming in iOS 14.2. The update is already live so you should be able to download it already.