Hi @Dylan_Eddy ---- Thank you for touching base with me and sharing the results of the proposed test, very appreciated!
Moving forward, based on this observation would it be possible for you try testing with the NAS mounted directly to the router, thus bypassing the mentioned managed switch? Not saying that the switch is the cause here, but we have seen issues with these types of devices crop up with these devices in the past ( Example: #1, #2, #3 #4).
If this test does happen to yield a positive result, I would recommend enabling flow control on the switch, as we have seen it help other users.
Furthermore, can you please verify that jumbo frames are not being used with the NAS.
-Eric