Thank you for the answer. Did the firmware update in the morning and during the day could not catch any offline events. After returning home I checked Homebridge logs and found out that the light went offline twice during the day. The periods were short (under 10 min each) though in opposite to the previous day when the light was offline four times 20-60 min a time.
So it seems to be more stable but I keep monitoring during the coming days and report back.