PROBLEM: animating frames get 'overtaken' by a black space

It may be that the behavior of adjustment layers in FCP changed at some point in the past few versions. Since adjustment layers are essentially Titles, that may explain why transform effects are not behaving as you'd expect.

A possible insight into this might be gleaned from watching this:

 Next Level Ken Burns 

So, it may be that something changed from the version you were using previously to the current version.

However, using effects presets instead of adding an adjustment layer and compounding the clips may be a more efficient solution.

Hope this helps. Cheers.

P.S. - I have no idea why the compound clip method isn't working. If it should work, even if it's not the most efficient way to do this kind of thing, that might suggest that it's a bug (Apple probably wouldn't care to hear about issues with adjustment layers, as it's not an actual part of the application, being a hack). Perhaps, someone else can chime in with a more thorough or satisfying explanation...