Walkman not displaying all playlist songs

[randomventures]

I have a NW-ZX100 Walkman. I have a playlist (.m3u) with about 600 songs on it and have noticed that on the Walkman itself it only displays and plays 521 of these songs. The file itself seems to be fine and all songs are present on the device. The songs that are missing on the playlist can all be played on the device outside of the playlist.

Any ideas? 

There is another playlist where the same problem seems to exist. This one has 535 songs on it, but the Walkman can only see and shuffle 532.

It's weird, it doesn't seem to be a hard song cap (which would make the device useless anyway), since the numbers are different.

[randomventures · Accepted solution]

I seem to have found a solution, but in case this helps anyone else:

If there are non-standard characters in the filename of a track on a playlist, it won't show up in the playlist on the Walkman (even though it will show up and play normally in the general music folders).

If there are too many tracks like this in the same playlist, it will apparently also start hiding other tracks, even if they don't contain any non-standard characters. 

Fixed the filenames on a few tracks and all the other tracks now show up in the playlist as well.

Very odd.