I've a suspicion it's due to tag version incompatibility. For example, iTunes has limited id3 tag abilities & has problems reading the more advanced ones.

I did read a year or two ago that those hexadecimal codes can be converted. It can be either a language or font issue on original computer the tag was set. The answer was unicode or something, I can't remember now.

So I am not totally sure how to overcome it, but those possibilities above as causes.

If you have any other mp3 tag programs, check whether they can read those comments, then convert them over.

From what I just googled, the standards for tagging can be a bit broad, as such problems may result from tagging in a particular program when then the tag shows up in another that has a slightly different definition or approach to the tag.

I googled to not much avail Apple - Support - Discussions - random id3 tag changes ...

.ataWhat?:. (half way down page)