Link trace data loss

[XTUxiongda]

In the morning，i Received five warning messages。so, i use these traceid to query trace in the skywalking UI.
At the very beginning, I found one, but after a while I searched again and couldn't find it.
So I went directly to elasticsearch to query the sw_segment-20221028 index, and found that only one of the traceid data was stored in it.

my skywalking version is 8.6.0
agent.sample_n_per_3_secs use default -1

question:
1.Is there any reason why it can be found at first but not later? Is there any automatic cleaning mechanism?
2.If there is a cleaning mechanism, why is only one of the five stored in the storage?

[wu-sheng]

Keep submitting things to overload a community channel, #9862 (comment). Locking.