I found an error on a CTR and would like to file an amended CTR. If I do so, is the corrected error still an issue in an examination?

The error happened and filing a correction doesn't undo that error, it just provides FinCEN and law enforcement the corrected information. That said, a single error would not normally result in an "issue" in an exam. A pattern of errors is likely to.

Examiners look much more favorably upon issues that are self-identified and self corrected. Was the error caught through your normal quality assurance processes? If it was, then that demonstrates that your quality assurance processes are working.

To show that your BSA Program is working, also document any follow-up training that was done with the employee who made the error. If this was an isolated occurrence, it most likely would not be a concern during an exam.

Thank you both!

Probably depends on the mood your regulator/examiner is in that day.