We have temporarily turned off the quick buy function for multi-variant products to double check.
You will be given a link to the single product page to choose from variations before being added to your cart.
We will check this issue again and update the fix in the next version.
I fixed all the problems for you, however what did you customize or update the theme which resulted in loss of previously fixed customizations.
Please do not update the theme for the time being to avoid losing your repaired customizations