We witnessed a but in the /Orion/NetPerfMon/Events.aspx page (in both 12.0 & 12.0.1).
When filtering in the events page, using the custom filter, the time stamps used do not match.
We suspect that the custom filter does not take into account the difference between local time and GMT.
Doing the same thing thru the Message Center is working fine.
I was able to reproduce this also in SolarWinds' demo site.
This was confirmed by support as a bug.
Simply be aware while troubleshooting