With ver 6.0.0.11, I made only one SVCD and, after noting this behaviour, thought it may have been caused by using an existing Version 5 project file, so I recreated the project from scratch and burned the CD again - and the problem went away.
I've since updated to ver 6.0.0.15, though, and today I burned eight SVCDs, each one as a new project (not using any previously-existing project file), and every one of them has this problem. I haven't tried re-burning them yet but, hey, that's not an acceptable fix even if they do correct themselves!

Again, the problem has not occurred with regular VCD burns, only SVCDs, and all of the MPEG2 files I've added to these SVCD compilations have passed Nero's standard-compliance checks without a hitch. These SVCDs play perfectly fine, otherwise. I've never had this problem with any prior version of Nero.
I've read all the posts in this forum, back to when Nero 6 was released, and didn't see any mention of this problem - which is a little worrisome 'cause, if I'm the only one having it, it's too weird. If anyone can reproduce this, I'd like to hear about it - and if Ahead knows about it.
Thanks.
- PBear