Audio problems with iMovie 11

Hello Community, I am having an issue with iMovie 11 and audio and thought maybe someone could advise.

One of my eveny libraries from a few years ago has been somehow compromised and when I playback the video there is no sound.

There is sound on other events, and there is SOMETIMES sound in the projects that used the events

When I reveal the clip in the finder there is NO PROBLEM at all (thank goodness) with the clip.

Is there anything I can do to jolt iMovie to rescan or reimport the contents of the event so that I may work with the files without audio issues?

Of note, at the time the files were imported into iMovie everything was fine. There must just be some bug somewhere that is messing things up.

Any thoughts or suggestions will be most welcome!