I did a movie of a model with two section planes. The SU8 movie included a section moving through the model. It came out perfect. I tried a reduced version of the movie with Irender nXt, less time between frames and no pauses. The movie didn't show the section planes as in the SU8 movie. My problem was after the movie was finished, when I clicked on the scenes which had the section planes, the section planes were no longer in the model. ??? I saved the model with another name. When I brought it back ... no section planes. When I bring back the original model, the section planes are there.
I hope I've made this clear. It seems the movie removes the section planes from the model.
We will have to take a look on how section planes work for movies.
I doubt if we make any changes to section planes during the movie. But we could take a look at that. We do process layer changes at key frames, but we do not process any of other type of changes - such as section planes for sun position.
A single section plane should work properly for the entire animation, but no changes to section planes. If this is not working, let us know.