After FW update I noticed that following modbus registers values are kept 0 between times 24:00 - 1:00, so right after midnight.
Mobile data received today (SIM1) 185 186 2 32 bit unsigned integer
Mobile data sent today (SIM1) 187 188 2 32 bit unsigned integer
Rest of the day registers are working normally and values are valid.
I updated FW at the same day when day light saving was activated. Is there issue with new firmware or time with day light savings?