How to resolve 'Missing Plugin' and greyed-out R3D.NE files in Final Cut Pro 11?

I've spent several hours testing this on my Mac Studio using various R3D-NE clips, and thus far, I can't reproduce it.

Are the "Missing Plugin" clips red only in the timeline or also in the Event Browser? If you select one of those red clips in the timeline and do SHIFT+F, that should display the parent clip in the browser. Does the clip show up there, or is it also red in the browser?

Right-click on the clip in the browser and select "Reveal in Finder." Does it show up in Finder? If so, where is that clip located? Is it on your hard disk or a camera card, or what?

If the clip ever shows red in the Event Browser, select that clip, do File>Relink Files>Original Media, but do not relink it. Rather, look at the bottom of the relink pane, and in grey letters, you will see the pathname where FCP expected that clip to be. What is that location on your machine? (Again, this is only if the clip is red in the browser).

The image you uploaded is the FCP import dialog, before import actually takes place. Are you importing from the card using "Copy to Library?" or "Leave Files in Place?" Are the greyed-out clips shown in your import dialog the ones with problems?

Does this happen on a timeline with no effects? What if you duplicate the timeline, open that, select all clips with CMD+A, then do Edit>Remove Effects. Does the problem ever happen then?

Does "done everything" include deleting the preferences?

I forgot to add, when troubleshooting cases like this, it's better to copy all files from the camera card to a local hard drive, then import from there using "Leave files in place."