timestamp – In mysql, system_time_zone does not reflect summer time changes, is not it a bug?

If an Ubuntu machine was in the "PST" time zone and the 10th of March 2019 at 02:00, its time zone is replaced by the "PDT" time zone in order to take into account the changes in the time of day. summer, this change is immediately reflected in the SYSTEM_TIME_ZONE server of mysql 5.7 that runs on this one. Will it also update the value from "PST" to "PDT"?

According to my observations, it seems that the answer is "NO", but then, how does MySql adapt to the changes of the summer time, because I can see it take effect at the value "timestamp" inserted.

Let me share example:

My Ubuntu machine was in the "PST" time zone and its current time zone is "PDT", but the mysql 5.7 server installed there always displays @@ global.system_time_zone as "PST".

However, I also find that none of the records having a timestamp column has a b / w value of 2019-03-10 02:00:00 to 2019-03-10 02:59:59 c & # 39; that is to say that a time difference of 1 hour takes place in accordance with the summer time.

To summarize,
1) are my observations correct?
2) If yes, is SYSTEM_TIME_ZONE not updated is a bug that should be fixed?