I'm testing NPM, NCM and SAM in my Lab (Orion Platform 2018.2 HF4, NCM 7.8, CloudMonitoring 2.0.1, NPM 12.3, DPAIM 11.1.0, SAM 6.6.1, NetPath 1.1.3).
I tried to change time on the report Average CPU Utilization - This Week from This Week to last 2 hours. Whatever I changed on date/time settings of polling engine and tested browsers (Chrome, IE, Edge, Firefox) on Ubuntu, Windows 10 and Windows 7 workstation - the result on displayed report was always the same:

With small exception in Firefox and Edge showing values on horizontal axis in the format I wanted (HH:mm). On the Summary home page time format was different depending on local settings on workstations :
or
.
While editing report I see on the Summary Tab correct format of time:

I will have to implement some bunch of reports for my customer soon and I know that AM/PM format of time is absolutely not acceptable. I'm wondering if there is any bug or I missed something.