Premultiply Alpha...

I just got bit by the Premultiply Alpha option in the Motion Export... Or so I thought:

What happened?  I edited my graphics into FCPX Timeline, and added Basic Titles above them, as seen in the below Timeline:

While cutting and previewing, all was fine (I never render in FCPX, Background Render is always turned OFF.)
After Exporting though, there were jumps in the background colors when the Titles appeared on-screen:

Clearly, before the Title shows up, the Background color is darker (wrong.)

When the Title pops up, the Background color changes.

Why you would ask?  Well, I had a semi transparent background in my Motion graphics, that's why.

OK, so I thought let's Export WITHOUT Premultiply Alpha.  I did and I got this:

Here it's all good, no changes before / after the Title.

Could it be that the proper way to export from Motion in this case is without Premultiply Alpha?  ...

Turns out, I should have added a Background to my graphics in FCPX!   Like so, in this case a Custom Generator (set to black):

The results:

All good this time!