timestamp issue

[happymoment-s]

nebula 3.1.0 (nebula-java : com.vesoft:client:3.0.0)
spring boot/java

I am using timestamp in the property of vertex.
https://docs.nebula-graph.io/3.1.0/3.ngql-guide/3.data-types/4.date-and-time/#timestamp

If the vertex is stored below a specific value (ex:1638365289), it cannot be searched with a FETCH query.

When I set an edge to the corresponding vertex and execute GO query, _EMPTY_ value is returned.

1. Is this normal operation? Or is it a bug?
2. A specific value that cannot be saved keeps changing (continues increasing)
   (For example, if I save as 1638365289, it is not searched, but after a while, if I save it as 1638365289, the search works well)
3. When saving, do I need to handle an exception so that a specific value is not saved? (Is it possible..?)

Please check. thank you

[xiajingchun]

Could you share the schema of the tag your created? And show me the nGQL pls. :) About how you inserted the vertex, and how you did the search?