Currently shares which are already expired do not get cleaned by cron.php. If you have a look at monitoring => shares the information is not valid, cause expred shares are counted.
If you login to your account and click on “Shared with others” the expired shares will get removed from Table oc_shares. Afterwards monitoring => shares is displaying correct amount of shares.
Of course i can not login with other accounts to trigger cleanup of their expired shares.
I do not want to cleanup expired shares directly in the database.