@Ronan-Lacroix - yep the time is but the zz is the timezone. SO below an example of the time I just retrieved from your NB-IoT network (at 17:16 PM local time).
The timezone is +8 quarters of 15 minutes. So UTC +2 hours. Now I assume that the timezone is changed for winter and summertime (DST).
So I assume that in winter the following will be returned (when local time is 17:16PM)