I'd use FMP to open and recover the file. Even though the file opens successfully with FMP, it may be damaged.
If the recovered file works normally, I'd still replace the newest undamaged backup I can find. (I routinely save 4 weeks worth of backups and then copy one of those each month to a "30 day back up.)
While FMP's recover tool has improved over the years, it's still "best practice" not to use a recovered file--there's just no telling if the "fix" was 100% correct.