The free month is real and genuinely included with digital pre-orders. The detail that catches people out is in the fine print on PlayStation's official product page: the month auto-renews into a paid subscription unless you cancel before the renewal date in your account's subscription settings.
The offer must be claimed through the GTA+ product page after pre-ordering, and it must be claimed by March 31, 2027. It isn't applied automatically just because you pre-ordered — you have to go claim it.
If you want the free month without continuing into a paid subscription, the practical approach is simple: claim it, then set a reminder before the month is up and cancel through your platform's subscription settings. Cancelling generally keeps access through the end of the paid-for period. Exact steps live in your PlayStation or Xbox account settings, since GTA+ billing is handled by the platform.
Most GTA 6 sites list "1 month of GTA+" as a straightforward bonus. It is a bonus — but a bonus that quietly becomes a recurring charge is worth stating plainly. That's what a facts-only site is for.