Download and install action

[Frisle]

In some cases installation of an app create a record with "download" status in others - "install"

"Install" means that installation done with a success. So the record has "success = 1"

And in what cases if installation were success the record has "action = download"

For example here is the three install action ( zpm "install PackageName" ). And all three events were success. But record has "success = null" and "action = download"

I'm a little confused at this point. How are installation events handled?