Just to update on my issue. I found that the cause was the customer adding multiple options to the cart too quickly on the product page. They would add the second option before the page fully loads resulting in the variation id not being added.
This is more a workaround as I realize this shouldn’t happen but I forced a redirect to the cart page after any option added forcing the customer to go back into the page to add additional options. This gave time for the page to load and haven’t had the issue since.
@amc11 have you found a solution to this?
I seem to have a similar issue that is very odd. In one order a variation can be added fine but then another variation’s _variation_id is set to 0 in the order meta.
Looking at the product and database the variation looks fine so I’m not sure why certain variations don’t add correctly.
It seems to happen randomly as if I test adding the same product variations to a test order it all goes through fine.
So even if I update plugins, clear caches, etc. it’s difficult to test if the issue is sorted because I don’t have anything specific to test for.
