When a salt is generated, the order of the characters is always the same as the order of the salt sources. This makes the salt more predictable.

To demonstrate:

Order is always uppercase, lowercase, digits, symbols, then Latin 1 supplements. Changing the order of the salt sources just changes that order but the characters are still grouped together.

Instead, the salt should be generated with characters from the sources in a random order. So instead of something like "prayers851{?" the password could be "prayers5{18?" and the order of the salt sources wouldn't matter.