Hello,
Yes you last test created two orders for the same "hour", but the previous one, you can see that there is few minutes between.
So I don't think that HikaShop (or HikaMarket) is duplicating the orders. Afterwards, it could be something related to a plugin ; some payment plugin can create orders in HikaShop (like paypal express, amazon checkout...)
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.