Hi,
Even if I don't see anything related in the changelog, please be sure to use the latest version of HIkaShop in order to have the latest patches and improvements.
It is possible that your issue will be fix just by getting the latest version.
In any case, please provide details about your discount configuration so we can see to reproduce your issue in one local website.
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.