Snooze only lasts for one minute

[THG]

I tried the wake-up call manager, and when the application call back and ask you to press zero if you want to snooze for ten minutes, it call back after one minute.

Edit: I tried again and now the snooze lasted for 17 minutes.

Third time it lasted for 13 minutes.

Fourth time only two minutes.

Fifth time immediately after i hang up the phone.

It's kinda random.