Hello,
The code for that part is in the HikaMarket helper "shop/order_backend".
At the end of the fonction "processView", there is the part which handle the overrides for the order display in the front-end.
There are just 2 cases.
Case 1 : There is only one single vendor for the order, and the setting "vendors in cart" is configured to "one vendor".
> The override of the store address is done.
Case 2 : (if case 1 is not validated and) There is at least one vendors for the order and the setting "display sold by" is enabled.
> The line "sold by" is added in the product listing of the order.
You are in the case 2, which means that your order have products from several vendors because your setting "vendors in cart" is set-up with "one vendor"
When "vendors in cart" is enabled, the old orders are not modified, it will just enable the restriction for next orders.
I don't know how you performed your tests and your screenshots are not completed ; so we are not able to verify your data.
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.