Style Variant Coming again and again after deleted

[exoneon]

Hi,

I delete variant from backend in the product below, and it reoccurs after sometimes (may be after buyer purchase item).

Then I go to product backend, and delete it again. How to fix it?

Variant: UV Printing / Indoor / 35 Inches

https://orantneon.com/products/custom-led-neon-signs-for-business