de0u falae alarm, i think I triggered the clock's misbehavior by split tunneling something that is involves in the clock workflow. now implying same step as describes above, time.gov shows device clock being ahead about half a second constantly i mean immediate reboot or a shutdown for few minutes, result is pretty much the same.
next i'll figure out what instance it is.
above statement that split tunneling was not the reason, because a weird thing happened. reset app preferences wiped the vpn from settings app and when attempted to connect from inside the vpn app i was getting some weird response 'vpn permission was denied when creating the tunnel. please try to connect again.' and network was not available , seemed like vpn was loop blocking itself from network, even there was no vpn in settings. no crashes and reboot fixed everything then.
by the way there was no warning that usually follows attempt to reset app prefs, i guess it was part of the bug.