Pretty sure that's the case.
There's no such thing as a clear user, because they're different (orthogonal) events. There are two binaries that compose into the four (ignoring enabled/disabled) possible states for an alarm:
unacked | acked | |
---|---|---|
active | active, unacked | actived, acked |
cleared | clear, unacked | cleared, acked |
So we capture an AckUser (ideally) when you move from unacked -> acked for a given event, but there's no user associated with an active -> clear transition, because that's happening whenever the alarm's condition is no longer met.