A bank files a CTR that it later learns it should not have filed, due to aggregating transactions that should not have been part of the tally. Can this be amended? Can the CTR be rescinded? Or is this the type of issue that the bank should be contacting FinCEN about directly?

There are no takebacks for CTRs. All you can do is note how the error was identified, and procedure/process changes that were implemented to keep it from happening again and any training that you provided to staff.

The only process FinCEN has for CTRs filed in error is to surpress duplicate CTRs.

Thank you. As we never came across this one previously, I was unsure how to proceed.

If this had been a case in which, after carving out the transactions that should not have been included, there was still enough to report, you would have needed to file a corrected CTR. But, as Brian reported, you can't just wipe out the filed CTR completely.