The discrepancy you are seeing is almost certainly a data entry issue rather than anything reflecting his actual legal situation.
InmateAid's inmate profiles are populated in part by information submitted by members of the community. When someone adds an inmate to the database, they enter what information they have at the time, and that information is not always accurate or up to date. A well-meaning person may have entered an incorrect release date, a date from a previous sentence, or simply guessed based on incomplete information. The platform does its best to verify and update records but with over two million inmates in the database, errors do occur.
The InmateAid profile is not the authoritative source for release dates. The official source is always the state department of corrections or Bureau of Prisons inmate locator for the system where your boyfriend is housed. Those databases pull directly from the corrections department's own records and reflect the actual calculated release date including any good time credits and adjustments.
If you want to verify his actual release date, search for him on the official government locator for his state. In Georgia that would be the Georgia Department of Corrections offender search at gdc.ga.gov. That record is what matters.
If you would like InmateAid to correct the information in his profile, email aid@inmateaid.com with his correct details and the team will update the record. Accurate profiles help other families searching for their person, so the correction is appreciated.