iMovie long fade to black
I have one single clip about 10 seconds long. I'd like the last 4 seconds or so to be a slow fade to black. I insert "fade to black" transition to the end and change "1 sec" to "4 sec". When I play the video, it starts to fade 4 seconds before the end of the video, but the fade itself only lasts about a second then the remaining 3 seconds is black screen. I'd like to slow the actual FADE down to 4 seconds. Is there any way to do that? Thanks!
MacBook Pro 13″, macOS 12.6