Except on a beat to windward, while a boat is less than two of her hull lengths from a leeward boat or a boat clear astern steering a course to leeward of her, she shall not sail below her proper course unless she gybes.
The problem is that it was on a beat to windward... where the rule isn't valid . I don't know if this is a general bug in VSK2 or only for our modified team race courses. The latter may be the case since we use the original seperation top mark as bottom mark. VSK2 may have defined "beat to windward" related to the original marks usage...
Just keep this in mind when you sail low on the beat to slow your opponent or prevent him from tacking.
Harald