I am having this issue as well. I have a product which includes a t-shirt and “t-shirt size” is a required field. When paying via PayPal obviously PayPal doesn’t natively send back “t-shirt size” as part of the customer data. This, however, doesn’t seem to matter as woocommerce just accepts the response from PayPal and takes you to the “review” page for you to review the order, and then “confirm” the order via the button at the bottom.
This is an issue because confirm order then fails because the required field has not been filled out, but there is nowhere for a customer to fill out “t-shirt size” on the order review page and at no point did they ever check out through the traditional check-out page so they never saw that option.
What is the suggested approach to using paypal with required custom checkout fields?