Losing transform on underlying clip in compound clip

I've created a compound clip from a storyline. The goal is that I can transform a whole sequence to a smaller frame within the project frame. But I also needed to do a few scale transforms on the original clips. So I opened the compound clip, selected some clips and applied the "Scale (All)" adjustment (slightly larger to crop out a lens ring from the frame). If I look at the unadjusted compound clip in my project after this, the scale adjustments seem to carry through. However, when I apply "Scale (All)" and some changes to "Position X/Y" to the compound clip itself, then the underlying clips revert back to their unscaled sizes. Any ideas why this might be happening? I know I could keyframe the compound clip to deal with this, but I'm wondering why the expected thing isn't working.

If I am following your description correctly, that is not what should happen. The first thing I'd do is make sure in Preferences that Background Rendering is turned off. Then delete all render files from the Library (via File menu).
What version of macOS?
What version of FCPX?
What model/year Mac?

Thanks for idea. I'm in the middle of a large project and it would consume a lot of time to wait for files to re-render after deleting them all. Similarly, I'm going to avoid upgrading to 10.4.9 for now.

macOS 10.15.6, FCP X 10.4.8, 24GB RAM in 2012 iMac 27"

Why would you wait for all your Timelines to re-render? Is there a reason you need all your timeline rendered? And FCPX will only re-render as you open timelines and needed it, not the whole Library at once.

And if it is a currupt render file, you may not have a choice but to delete all your render files.