why is it that logs that haven't changed come up with a differant inode with ever run of tripwire:

Modified object name: /var/log/cron/errors.1.gz

Property: Expected Observed
------------- ----------- -----------
* Inode Number 312199 311981


Modified object name: /var/log/cron/errors.2.gz

Property: Expected Observed
------------- ----------- -----------
* Inode Number 312047 312199