I think this is a bug.
Do you open a ticket for team support?
I suspect it is bug as well. Especially in Perfstack horizontal axis shows AM/PM format in all browsers (Chrome, Firefox, IE, Edge), I have tested.
I didn't open any ticket because I'm independent consultant and I work for few Customers which have no problems yet. I found the problem on my Lab (test) installation
In near future I will update installations for customers SW2168532 and SW22165292 so I'd like to have this problem fixed before I need to make any ticket from those customers IDs.
So please address the issue to relevant recipients.