Are you sure the files in question do not have damaged VBR headers?
I am.

All the files were fixed using mp3tool (from the Lord ) recently, even though they should have had correct VBR headers right from the start (all encoded with lame >3.80).
I think though, that some of the files might not have VBR headers at all (but very few) but some files which exhibited the behaviour definately are in perfect shape, including correct VBR headers. One file was definately CBR encoded.

cu,
sven

PS: What was that "Ahem" post linking to? I mean the post you deleted again (but I got it through mail anyway, just without any HTML tags)? I guess you were linking to some FAQ entry?