I think Dan is probably right about it being vair. I posted this: https://www.cambridge.org/core/journals/antiquaries-journal/article/garments-so-chequered-the-bible-of-citeaux-the-bayeux-tapestry-and-the-vair-pattern/8E18D022A3032C26F61D3BBA60072428 a whlie ago on AA and forgot they used vair for more than cloaks.