Morph cut effect not working on flattened clips in a multicam sequence

I have a multicam sequence and want to add a morph cut effect to a cut point.  Didn't work on the multicam clip, so I flattened the clips and tried to add it to those.  It says "Analyzing in Background" but the effect doesn't render and it doesn't show any of the effect settings in the Effect Controls and "Analyze" is greyed out.

PP 25.6.3

MacOS 14.7.1