Hello,
Stripe V2 plugin store the Stripe Customer ID in the user object (in the database), under the serialize "user_params" column.
While the plugin do not make the difference between development and production environment, the customer made for your tests are also used for the production.
So you need to clean the "user_params" for these users so they won't have any stripe account id anymore and the plugin will re-create them in production environment.
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.