Apple has updated iMovie and GarageBand for macOS. Both upgrades are available at the Mac App Store.
According to Apple’s release notes, iMovie 10.1.14:
° Fixes an issue that prevented media from appearing in the Photos library browser when using iMovie on macOS Catalina;
° Prevents an issue that could lead to visual artifacts appearing onscreen for systems with Nvidia graphics cards with the Reduce Transparency accessibility preference enabled;
° Resolves an issue in which thumbnails wouldn’t update when skimming titles, backgrounds, and transitions in the Browser;
° Improves overall stability.
According to Apple’s release notes, GarageBand 10..3.4 providers stability improvements and bug fixes.