Hi,
Yes, this is a side effect of the way we retrieve the user groups.
But every account is "public" so there is no real problem to be in "public, vendor" because, being "vendor" is being "public" too.
We will see to improve it but don't worry, it does not have side effect, it's not a critical issue.
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.