So, this morning, with some orders we were able to validate the picking, but on the delivery, the button validate just wasn't there, instead, there was the button "Check Status". Nothing was changed on our workflow... This is not from a manufacturing order. Anyway, when pressing the button "Check Status", we get this error: 

Invalid Operation

There is no any instance is configured of seller False

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Weird English, but we do have a vendor assigned to the product.

I wonder if this was a breakage from Odoo's weekly updates? Anyway, our partner made a quickfix to make the button "Validate" to appear. And all was good. Just sharing here and wondering if more people were experiencing this problem.