1) yes i restart my mac. It appears since the last Update, once or more times a day (with or without restarting the mac on this day doesnt have an effect.
2) occasionally. No my Mac is not under heavy load, the Load Avg: 0.48
3) no nothing updated or installed new, i make all updates from Apple "1Week later" - i think the problem start after teh last Alfred update.
i try to open "Activity Monitor" next time