Stephen,
I just tried the same password on a new account 15.7 and it worked fine. I will try this on a later version of code and let you know, in this case I created a new account "bill" and my password policy looks as follows:
RDU-EBC-BDX8-2.2 # sh accounts password-policy---------------------------------------------------------------------------
Accounts global configuration (applied to new accounts on creation)
---------------------------------------------------------------------------
Password Max. age : None
Password History limit : None
Password Min. length : None
Password Character Validation : Disabled
Accts. lockout on login failures: Disabled
Accounts locked out : No
-----------------------------------------------------------------------------
User Name Password Password Password Password Flags
Expiry Max. age Min. len History
Date Limit
-----------------------------------------------------------------------------
admin None None None ---
user None None None ---
bill None None None ---
-----------------------------------------------------------------------------
Flags: (C) Password character validation enabled, (L) Account locked out
(l) Account lockout on login failures enabled
RDU-EBC-BDX8-2.3 #
: