Hi,
HikaShop does not touch or interact with the Joomla session.
So we don't know why you have these messages and I don't think that there is something in the HikaShop product edition code (or in the backend) which can be responsible for that.
More than HikaShop ; your joomla website also have (system) plugins.
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.