"Return arrived in return FCs" meaning?

Not seen this before on returns tracking - "Return arrived in return FCs"

I'm reading this as the item has been returned to an Amazon Fulfillment Centre? Is that what this means?

Puzzled because we have an A-Z claim open for a refund of a return that has never been sent back to us, and it looks like it's gone to an Amazon warehouse. We don't and have never used FBA, so it looks to me like we're losing an expensive item and taking an ODR hit for an issue with Amazon/Evri returns process misdirecting a parcel

(Yes, we have our returns address entered correctly)