Hi,
Can you please indicate your HikaShop and HikaMarket version number ?
If you targeting a product sold by a vendor, you have to activate the option "discount target vendor".
It is something which will be improved in the next HikaMarket release but for the moment you have to activate it if the product have a vendor.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.