With version 2.7.0 on menù item "K2 Categories" front show string

K2_DomPMUTCE_DomPMUTCE K2_DOMPMUTCE_MAR+0000UTC19

On single article visualization it is shown string:

K2_VenAMUTCE_VenAMUTCE K2_VenAMUTCE_Mar+0000UTC00

The missing field concerning date and time creation of article

IMGUR album - 2 screenshots
imgur.com/a/G1cxH

Hello,

It looks like a language string is missing.
Most likely it was in K2's language files instead of the overrides, so it was overwritten.
You need to either locate that string and correct the issue or contact the template's developer.