Virtuemart - Coupon use causes shipping cost drop away

New coupon: Coupon code, manufacturer specific, and specific only to product price. + Automatic coupon in use.

Onepagecheckout ( from Virtueplanet.com) in use

Problem is that when cart have product from manufacturer what is defined to have -30% discount - Shipping cost disappear totally.

It wont came back when cleaned cart and selected different product from different manufacturer. Then i deleted coupon + automatic option but no luck.

I didnt figure out what to test next but then i run ccleaner to get rid of cookies. It worked fine with other manufacturer products. Shipping cost came back. Didnt test again with coupon.

Any suggestions how to solve this behavior?

Joomla! 2.5.6
Virtuemart 2.0.26d
Awocoupon Installed Version: 2.2.6
Onepagecheckout 2.0 version.

Hello,

My first suggestion would be to disable the onepagecheckout and test it on virtuemart defult checkout. If you do not receive the same behavior, then you would need to contact the opc developers.