Strange charging behavour in DESS

Hi all,
This happens sometimes, during charging ( following estd. SOC curve ), system starts to discharge 1 hour too early, then continue charging for 1 hour.
Look below at 06:00-06:59.
Batt bank is 900 Ah, 48V., 3xMPII 5 kVA, MPPT 450/200, Cerbo CX, VM3P75CT, FW 3.52
Ideas ?
/Erling A.