3D Shadow No Longer Rendering

OK since I apparently can't delete my own posts, I might as well post that I found the problem! Apparently, if you apply the fade in/out behavior to a group, it kills the 3D shadow for any objects that are in the group, even when the objects are visible. Doesn't make any sense, but this is what I'm seeing. My shadows were working fine until I applied the fade in/out to the entire group. As soon as I remove the objects from the group, or delete the fade in/out behavior from the group, the shadows reappear. I tried this in a brand new project and saw the exact same results. Surely this must be a bug.

I've made numerous Motion projects that use 3D shadows and never had any problems. Then yesterday day I noticed the shadows were gone in a project I've been working on for days, whereas the shadows had originally worked fine. I've tried everything I can think of it fix the problem, short of starting from scratch. What I have done:

The project is 3D.

The group that contains the objects is 3D.

The project has a spotlight, angled toward the object, shining on the front of the object, "shadows" is checked in light properties, the opacity is 100%, the color is black, and the light is on.

The objects and the group are set to "inherited" shading, and "cast shadows" and "receive shadows" are both checked.

"Shadows" is checked in Render settings.

The object is "floating" above the surface behind it so there's plenty of area where the shadow should (and once did) appear.

Despite all of this, my objects which were originally casting shadows are no longer casting shadows. Everything else in the project appears normal as far as I can tell.

I even tried deleting and re-installing Motion, and it still does not work. When I open older projects with shadows, the shadows are all working fine. If there's something I missed, please tell me.

Note: I've only been using Motion for a few months, but I've noticed this kind of mystery problem affecting all kinds of things. For example, I tried starting a new project. I added an object, and it appeared fine. I created a group for the object, and the object vanished. The bounding box was still visible. The opacity was still 100%. Literally nothing else changed, and I could not make that object reappear. I deleted it, imported it again, and it was fine. I even grouped it again and it was fine. But nothing short of starting over would make it visible again. I've had this exact same issue with a number of other objects and effects. In the beginning, I thought surely I was overlooking some simple setting. And a few times that was actually the case. But in too many cases, something will simply disappear or stop working and absolutely nothing I can do will fix the problem short of deleting the object or starting an entirely new project from scratch. Clearly Motion is entirely unusable if random things break and there's zero solution other than starting over again and hoping for the best.

Also, I tried editing my original post, and somehow the whole edited post ended up as a reply to my original post, and there's no way to delete it. This is insane. I'm going to bed.

Thanks for the information. The object that loses its shadow is an Illustrator file, which imports as a PDF. When I apply the fade in/out behavior directly to the object, the 3D shadow works as I would expect it to, and there is no "R" at any point along the timeline. However, when I apply the fade to the group, that little "R" does indeed appear next to objects in the group as soon as the opacity drops below 100%. Thanks for pointing that out, I hadn't even noticed it before. But then of course the 3D shadow immediately stops working for anything in the group. I'm glad to know that this isn't a bug, though it is really perplexing to me that you can apply the fade to any individual object in a group, but not to the group itself without breaking the shadow.