I think it's a bug, so please check this . Maybe someone could help me ..:
All-In-One Event Calendar (1.3 version) is NOT compatible with Budssypress 1.5.4 with ACTIVITY section. If Calendar plugin is active, buddypress tell me that I'm "active sometime ago" . All statuses wrote in less that 1 hour has the same info: "post sometime ago" . If it's more than 1 hour, all statuses working great.
It could be a daylight savings problem compability with All In One Calendar over the Buddypress . But I'm not sure.
Please, check this and - if it's possible - let me help to fix this... ;)