I believe I saw that someone else in the Forum had this issue but can no longer locate the question.

I sent the file to Support and they were able to confirm the Files work correctly. However, I downloaded the Beta version as suggested and attempted the submission 2 more times without success.

Please, any other suggestions?

Failed to build _______________ Android Files

An unexpected compiler error occurred

NilObjectException in
SCAndroidAppCompiler.buildXPUBContainer: