While an eviction is ongoing, an RN might want to issue a WriteUnique to the line being evicted. As section 2.6. (CopyBack Request order) says, "An RN-F must wait for the CompDBIDResp response to be received for an outstanding CopyBack transaction before issuing another request to the same cache line.", which is completely expected and reasonable.
On the other hand, Table 4-40 specifies that a regular eviction that answers with CBWrData_UD_PD is at state UD before sending the write data response. However, there is a time frame between the CompDBIDResp and the CBWrData in which the RN technically is still in UD but can already send requests to the same line. Since it is in UD, seems like WriteUnique should not be allowed, but from an HN's perspective, even if the RN sent the WriteUnique after the CBWrData, they may arrive in any order, as they are on different channels.
In that case, should the state of an evicted line be considered as Invalid after the CompDBID in regard to which requests can be sent?