Hello gentlemen,
As our Engineer has investigate the issue, we have found running the following command in terminal seems to be able to resolve the issue:
sudo mkdir /Library/Security/tokend/tmp sudo mv /Library/Security/tokend/CAC.tokend /Library/Security/tokend/tmp
We believe 10.13.4 does something weird with either the scoring of the cards or the reading of the cards because sometimes it would work correctly (read as CACNG or PIV) but usually it would read incorrectly (as CAC)
Therefore, please give the command above a try and see if it's able to resolve the issue afterward?
Hope it helps. Thank you!
BR,
Ivan