Batch Audio Artifacts

Whenever we batch audio files to MP3 about 25% of the files will be glitched and we cannot find a pattern. This happens in AME on any type of machine using the same MP3 Audio preset. The type of glitch Parallel Encoding settings is pretty consistent:

• scrambling the audio so the last half is spliced into the beginning
• adding a hiccup/pop at the very end of the file
• speeding up the entire audio file

I've tried a number of fixes like turning off the “Enable Parallel Encoding”, trying different machines etc to no avail.

Anybody else have this issue?