Every year we have numerous corruption requests after vacations. Unattended computer systems can reach their implementation limits or encounter hidden problems, like lack of space, HDD bad blocks, automatic updates, etc.
Firebird is a software too, and it has "popular" reasons to stop working while administrator enjoys roasted turkey.
Before vacations and after them we recommend to check the free space on HDD with database and HDD on backups, check the transaction markers state (gstat -h) for the gaps and limits and, if possible, perform full backup/restore cycle (with gbak -b/gbak -r).
These simple actions can save your database from "vacations' corruptions".