Time Machine exclusion grade out for a new SSD?

Been backing up 500GB internal drive and excluding 1TB Samsung T7 SSD and 500GB Crucial SSD successfully to a 4TB HD for a few months to my M4 Mac mini Pro. I decided to buy a dock/hub to get more ports and it came with an internal NMMe M2 SSD slot, bought a 1TB Samsung 990 EVO Plus to install in it, the hub is connected buyer thunderbolt, with the intention of moving the files from the external Samsung T7 to the hub with the Samsung 990 is, to my dismay I am unable to also exclude the 1TB NMMe M2 SSD.

Does anyone have any suggestions of why it might be greyed out?

The NMMe M2 SSD is formatted as APFS drive.

Also the 4TB HD is less than half full so no issues with it not having enough room.