Basically mbar and hPa is the same value, so the difference is not related to the unit used, but more likely how often the value is updated.
1000 hPa are equal to 1000 mbar , which is equal to 750 mm of mercury in a barometric column, which is 0.987 of the average atmospheric pressure, which on global average is 1013 millibars or hectopascals. While hPa is used in meteorology most weatherforecasts quote atmospheric pressure in millibar .
See https://www.weatheronline.co.uk/reports/wxfacts/Millibar-and-hectopascal.htm