Cross referencing with the .bin files that are available from synthparts.com: the two "CAS" chips are the two chips for the Voice firmware. It looks like the tape and voice version typo are likely caused by the faulty Voice Processor.

FYI- the U.S. made Xpander uses the 68B09P. Mine looks like it has a Rev. A voice board. I ordered the 68B09EP, as I read elsewhere that replacing it fixed the problem on a Japanese XP-1. It looks like the Japanese and U.S. versions use different CPU chips, as the "E" stands for externally clocked.