Renewal support of products that have a negative price group

I am unable to provide renewal support of products that have a negative price group?

http://www.xyzjunk.com/amember/member.php?tab=add_renew doesn't work?

http://www.xyzjunk.com/amember/member.php?tab=add_renew?price_group=-15 doesn't work?

aMember Pro 3.1.9 installed.

Temporarily fixed...

I temporarily fixed it --

This line 378 in member.php

} elseif ($v['price_group'] < -16){ /* N2 was < 0 */
unset($products_to_renew[$k]);

My groups go down to -15.

But a patch needs to be issued to allow negative group members to renew!