Couchbase automatic tasks after "Temporary failure received from server. Try again later" Message

first please consider this ticket.
when I encountered “Temporary failure received from server. Try again
later” Message, after many times(more than 4 days), RAM usage is high,
“Item Count” for bucket is not change and no any action side of couchbase0server services
I guess after “Temporary failure…” message, the couchbase automatic tasks encountered problem.
and there are two more questions:
1-I set alert config, why not couchbase send mail when it would throw “Temporary …” message?
2-in “General Bucket Analytics” in management console, which item should be abnormal when above message would be throw?
3-after that message, why not servers go back to normal point? I expect to ram usage not more than bucket ram specification and it should be less than of _specification size_when I set “full eviction” option for this bucket.