Ihnen fehlt GROUP BY , also wird alles gezählt, anstatt nach einigen Spalten zu gruppieren.
LEFT JOIN
(
select `ID` as `AuraID`, `Status` as `AuraStatus`, count(*) as `Aura`
from messages_aura
GROUP BY AuraID, AuraStatus
) aura ON (var.Poster = aura.AuraID AND var.ID = aura.AuraStatus)
