mistakes in stardates were made by all of the treks, in the kelvin timeline the first movie ignored the decimal point when 6 digits were read out, such as 223304 instead of 2233.04. However, there are 30 discovery episodes and when you compare it's inconsistencies in stardates to the other shows, for the same amount of episodes the other shows had fewer inconsistencies. TNG DS9 and VOY had a stardate coordinator which kept track of stardates and tried to keep them consistent, but due to human error and probably typos in the scripts, stardate mistakes went to air.