Since it is only two files that are giving you issues, you might also try just manually downloading them straight from your browser. It wouldn’t cost that much more time for only two rars, and it would eliminate the variable of the download manager.
Whatever you choose to try next, make sure to put the new copies of the rars in the same folder as their respective sets.
And you can use the same checksums I sent you to verify that the files have saved properly.
Yes, I did try the manually/direct download for these as well to no avail.