If I use the command-line smbpasswd tool to create a user and set or change the
password, the user is added properly in the smbpasswd file, and can validate
properly.

SWAT appears to be completely broken. If I add a new user, it tells me that I
must also enter the new password (twice, of course). Fine, except the user gets
inserted with 'XXXXXXXXXXX....' for the password!  If I then use SWAT's change
password function the password does get changed to what appears to be a valid
hashed value, but in fact the user can not authenticate. Comparing the hash to
the hash produced by using command-line smbpasswd, shows they are different. I
have no idea how SWAT is generating the hash.

For example, for the password 'hello', this is what SWAT generated:
test3:518:B8141342B814134248131342B0BA2008:481313424813134273696F6E002D352D:[U 
        ]:LCT-00000000:

But 'smbpasswd -Utest3', entering the same password, set it to this:
test3:518:FDA95FBECA288D44AAD3B435B51404EE:066DDFD4EF0E9CD7C256FE77191EF43C:[U 
        ]:LCT-3F6B6D4E:

What is extra weird is that running SWAT to try to change the password a 2nd or
subsequent time simply does nothing; the entry in smbpasswd is not touched.

I get this behaviour on both RedHat9 and RedHat 7.3...