Apologies if this is the wrong place to post this, I couldn't see an obvious place to raise a bug for a non-beta version.

If you haven't called group functions before disabling WOW64 file redirection, all subsequent calls to those functions return no results. The simplest test I can find is:

$rc = SetOption("WOW64FileRedirection","OFF")

$index = 0
	$group = EnumGroup($index)
	? $group
	$index = $index + 1
Until Len($group) = 0

Uncommenting either of the first two lines lets your group membership be printed, but with both commented out no groups will be printed.