They state that here and it's been stated there in the several years I've run Always Free VM's there: https://docs.oracle.com/en-us/iaas/Content/FreeTier/freetier...
Some people say that doesn't apply to PAYG users, I do not know about that for sure, I am a PAYG user since 2021 and have not experienced any reclamation issues.
I’ve been PAYG for several years now and have straight up idled the instances for months at a time and never been deprovisioned