Did you try deleting those books, using CoolReader itself, before trying the resend? I don't know whether that would work but it's worth a try if you haven't already.
On the other hand, if calibre metadata is important to you, have you considered the
Calibre Companion android app? It will manage your calibre metadata on an android device much better than anything else on the market plus you get to choose which reading app to use to do the actual reading of your books. It works seamlessly with CoolReader. It's very reasonably priced and has a free demo version so you can test drive it.