What is the interval of alert ignition in 3scale?

Issue

• Why does an alert not ignite twice within 24 hours? Is this specification?
• An alert can be triggered twice for the period of 'week', 'month', 'year', and 'eternity', however, it does not trigger twice within 24 hours.

• We have a customer who used up their daily allowance of calls this morning, but never received the 80% or 100% email alerts that are configured in the admin portal. They did receive them previously. Is this expected behaviour?

• I configured usage alert then sent requests to exceed the upper limit. I expected to receive alert mail immediately but I got it after several hours.