Shoppers are being prompted at checkout to update their contact info with their phone number at checkout. They get an error when trying to update it in cases of duplicate accounts.

Shops with MSM have an increased amount of duplicate accounts due to accounts being created from Shopify orders. Currently we are advised to NOT combine MSM and CS accounts, so customers have no way to update that info on their own.

Customers are unable to checkout in that case and have to reach out to the shop to manually update their phone number so they can proceed.