I think these are two different issues.
The problem is that the sort algorithm has problems with overlapping objects. As you look from left front onto the planes the bounding boxes of both objects are intersecting each other. I think the algorithm does a best-bet calculation with the object centers, which unfortunately results in incorrect sorting.
There are two things you can do:
A) support the sorting, buy changing the dimensions of the second or the first plane and/or give them a larger distance.
B) switch the logo to clip alpha. This way it will not be sorted and uses the fast Z-Buffer rendering. (But you loose any semi-transparency)
Font objects are somehow different. I do not know how they are implemented, but they do not appear as normal objects. I had the problem that they are not visible in render-to-texture output.
My suggestion: Move the black plane much more near the camera (and make it smaller). As alternative - use an overlay scene with the camera and the plane only. After fading you can even remove the scene ;).