Code review comment for lp:~percona-toolkit-dev/percona-toolkit/ptc-errors-on-slave-with-different-time-zone-1388870

Just to add that, also according to my tests, indeed it's a replication thing.

When doing insert on master, slave uses system_tz to do convert to UTC locally when inserting into a timestamp column.
When doing insert..select on master, slave also uses its own system_tz to convert to UTC locally when reading.