WORKAROUND:
The passwd command message is coming from the operating system and not Authentication Services therefore this is not something we can change. However as a workaround I would suggest using the vastool passwd <username> command which does return the correct message when a wrong password is typed:
-sh-4.1$ vastool passwd gboudreau
Password for gboudreau@i.ts.hal.ca.qsft:
ERROR: Failed to change credential:
Error 1: VAS_ERR_KRB5: Kerberos error
Failed to obtain credentials. Client: gboudreau@I.TS.HAL.CA.QSFT, Service: krbtgt/I.TS.HAL.CA.QSFT@I.TS.HAL.CA.QSFT, Server: idc01.i.ts.hal.ca.qsft
Caused by:
KRB5KDC_ERR_PREAUTH_FAILED (-1765328360): Preauthentication failed