I'm new here, so sorry for disturbing.
I've experienced the problem reported earlier.
In my opinion, trying to synchonize PC or to play with several clocks is a hard job. Maybe all the timestamps should be computed and converted to text server-side. Otherwise there's always a dependency on client's clock, which looks like a bad idea. As a proof : this bug exists and we are having a discussion about this problem.
My intuition is that a simple solution like an offset can lead to wrong information.
Sorry not to be more helpful.