iMovie imported clips in slow motion with no sound
I am making a video from clips provided by multiple people. They all play perfectly fine on the desktop, but several of them are in slow motion and without sound when imported to iMovie. When the problem clips appear in the event folder they have a "sunburst" symbol in the upper left hand corner. Any idea what's going on? I can slow the videos back to normal speed but they still don't have sound.
MacBook Pro 13″, macOS 10.15