Two HDs in a Wavlink dock - 100x difference in write time

I have two Western Digital DC HC530 (14TB) hard drives in a Wavlink USB 3 dock.

When I copy a file to the first HC530 from an inserted HD, the file transfers at 300MB/s

When I copy the same file to the second HC530 it transfers at 3MB/s. It does transfer, but 100x slower. No matter what Wavlink slot the HC530 is in.

Is this slow HC530 about to die? It’s SATA, it has no DIP switches that could be set wrong to slow it down 100x. I never tweaked its internal settings with any PC utility, either. What do you think? Thank you