What, you don't like Baldrick's answer? You won't like this either. Maybe bitrate, maybe recognition problem, maybe both. We must remember designers of various standalones have their own ideas. You're actually outside the specs anyway with mini-DVD. So it varies by player.
For instance: Putting SVCD on a DVD is NOT compliant. The various manufacturers put absolutely NO time or effort into ensuring playability. Guess what? DVD-SVCD does work on some players, even without header tricks. Similarly with mini-DVD. If it plays, it's a bonus.