I have a mix of .mp3 and .m4a files (sometimes both for one album, due to iTunes Match). With the latest version almost every m4a file seems to be failing. A few have succeeded so it seems like it is possible.
For example, a typical result I had was about 1400 successful and 900 failing - and the 900 that failed were all .m4a files, making up about 98% of the total .m4a files. The only error in the final report though is this:
Unable to save changes: Value of:false is invalid for field:COMPILATION
Most of these weren't compilations, however.
Any one else experiencing this? I'm probably going to revert to the previous version.