Ladies and gentlemen, we have a winner!

I hadn't realized the code in the module would be run after compile and before the calling script continued compiling.

I put some print statements in the main body of my module and sure enough, ARGV was being altered in there. I tracked it down with a few more prints and found it.

Somehow in refactoring a sub, I had left a

my $self = shift;
my $item = shift;
[download]

sitting naked in the main body of the module. Whee!