Yellow bowls in the last kingdom

Having looked at that sequence, I see, at the table, there are brown wooden bowls, and in the background, on shelves, much lighter-colored bowls.

There's nothing about them that suggests plastic or even glass.

It could be a much lighter-colored wood. Here is a pine bowl -

Here is a maple bowl -

Ceramics and tinted glazes have been around for thousands of years, so a light/white glaze could easily be in play if it was glazed. Also, clay bowls aren't just orange. Very often they are a very pale grey, almost white before glazing, like this one -

I have a bowl that I made in a class that I left unglazed so I could use it for clay pot cooking. It started out as a slightly yellowish near-white.

I don't think this was any kind of error.

EDIT: After checking in the correct timestamped area, my original assessment holds, except I'd say those are definitely wooden. They yellow and black-ish.

Here is an image of a bowl made from mulberry wood, which is pretty yellow -

and this is one of a maple bowl that has had a food-safe oil finish added, which has yellowed the wood quite a bit, but has darker discolorations, like the ones in that scene -

In the still shown, the reflection makes it like a highly glazed ceramic bowl. I don't see why there couldn't have been glazed ceramic bowls in 9th century Britain.