ive seen my cursor in-game lagging behind the hardware one in game, but this was on my old PC which was really slow, so if you have such a computer, look for a [ ] tick in the settings regarding "harware cursor" or something like it
Heroes of Might & Magic V and World of Warcraft have this option, on my old pc HOMM5 wouldnt run, and in WoW the option was unavailable, but now i have it on

and its all fine