Hello,
By "reloading" the page, you are re-sending the form data to create your "demo99" characteristic.
So, you're creating it a second time.
And if you refresh the page the same way, you'll doing it again.
What you're omitting in your workflow, is the browser popup which is asking you if you want to resubmit the form.
pasteboard.co/ke48Ya3CJuV3.png
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.