You can only have community property first of all if you're in a community property jurisdiction.
Once she sells the property to a third party, she is no longer the owner at all. Since she begins adversely possessing the property BEFORE she gets married, her new title in the property after the statutory period runs is dated from the moment she began possessing the property. Therefore, she received titled in the property before marriage, not during, and the property remains hers (since community property only includes property acquired during the marriage).
Granted I'm rusty on my property knowledge...
She gained title to the property after she was married, not before. An adverse possessor does not attain "retroactive" title once the statutory period runs. Title only vests when all the elements of AP are met, including the running of the applicable statute. Therefore, the property is community property, or marital property, as the case may be.