[web2py] Unexpected dash in URL

[pbreit]

I have a strange problem where a URL() tag is switching an underscore in the 
function name to a dash.

Code:
{{=A('contact %s' % (item.seller.name), _href=URL(c='default', 
f='contact_seller', args=item.id))}}
sam with {{=A('contact %s' % (item.seller.name), _href=URL('default', 
'contact_seller', args=item.id))}}

HTML:
<a href="/contact-seller/1">contact cheekob</a>

I have not done anything to my routes or anything else to swap 
underscores/dashes as far as I know.

Mac Version 1.92.1 (2011-02-16 15:04:40)