I have two screens. A window (app) of graphics runs on one, vMix runs on the other. vMix Desktop Capture app is NOT running. I have inputs:

1. Desktop Capture input of "My Computer" for window MyApp with color key for neon green.
2. Virtual Input made from #1, cropped to show only a portion of the MyApp window.
3. Virtual Input made from #1, cropped to show only a portion of the MyApp window.
4. Virtual Input made from #1, cropped to show only a portion of the MyApp window.
5. Virtual Input made from #1, cropped to show only a portion of the MyApp window.
6. Colour input with color transparent, with #2, #3, #4, and #5 as overlays in MultiView.
7. Colour input with color black, with #6 and some Stream inputs as overlays in MultiView.
8. Colour input with color transparent, with #1 as overlay in MultiView, cropped to show the same as #2.

Using 1-7, everything works as expected. #6 is a build up all the captured elements, with individual positioning, and it sits "over" the Streams in #7. It's essentially live video with a header and footer overlay.

In an effort to reduce render time impact, I created #8 as a replacement for #2. When I put #8 "in" #6's MultiView, it appears as expected. But in #6, it's missing, as if #8's transparent property has passed through to #6. If I change #8's color to colour bars, it appears "on top" of the Streams in #7, as expected.

So I think the bug is that a Colour input (with color transparent) used as a MultiView overlay for a Colour input (with color transparent) results in a masking situation in which the first input is not shown at all.

I can share a settings file if needed to debug.