Media Manage copy then import fails

I may not be doing this correctly, but... (Running Resolve 17b6 on Mac Big Sur.)

I have a timeline in my current project that has six clips on it. These six clips are associated with the movie files DSC_3339.mov through DCS_3344.mov, in that order, which I can confirm by looking at the File tab of the Inspector in Edit and clicking in turn on each clip.

I use File -> Media Management... then select Timelines and Copy. I check the box for the timeline and will Copy Used Media. I don't check Relink to New Files, which might be a mistake, but I'm thinking it may relink the current timeline to the new media and that's not what I want.

The copy works and in the target folder I have a sub-folder with the Project's name and inside that a timeline .drt file with the Timeline's name, plus the six clips that are used. I assume that this new timeline is linked to these copied clips.

I import the Timeline (File -> Import -> Timeline...) and its name gets a "2" appended to it because it's the same name as the original timeline. All fine, but then thing get weird:

I look at the imported timeline and I see the first clip is not the correct clip. (This happens even if I shuffle it to another location in the original timeline before copying: it's not just wrong because it's the first clip.) It's literally a different clip that does exist in my project but isn't used in the timeline I copied. When I click on each clip in Edit, looking at the Inspector's File tab, I see:

DSC_3334.mov
DSC_3340.mov
DSC_3341.mov
DSC_3341.mov
DSC_3341.mov
DSC_3341.mov

Which is crazy. So now two crazy things are going on:

1. I'm seeing DSC_3334.mov -- indicated in the Inspector and visually -- even though it was not in the original timeline. What I see as I play the timeline is in fact DSC_3334.mov. So the wrong file is playing correctly in the timeline. (That is, the clip is the wrong clip, but it is showing the file it claims to be showing.) This file is not in the target directory, so it's being pulled from the original media (for the project, not even the original timeline).

2. Other than that clip, I see what I'd expect for the other five clips when I play the timeline. But it's totally weird that the Inspector says the last four clips are the same file. They are most definitely different files and are not sub-clips or in any other way edited out of the same clip. They are different clips from the camera.

Maybe this isn't the way to do what I want to do. What I want to do is to keep my original timeline with its links to the original clips, and have the new timeline which should look exactly like it but be linked to the now-shortened copied clips.

I didn't check the "Relink to New Files" box because I assume that would relink the original timeline to the copied clips and I don't want that. I want the original to point to the original clips, and I assume that the copied .drt will point to the newly-copied (and shortened) clips.

Anyone else seen this kind of weirdness?

I remotely speculate that somehow Resolve is having problems with two different folders with clips of the same name in the same project. And maybe it also gets too many 3's so that "3340" turns into "3334"? It's very weird.