I’m guessing the cheaper ones don’t have sine-wave inverters (they use a dressed up square wave which can be produced by purely digital electronics) so quality of the output waveform is bad. The power supply of the laptop (or PC) ends up having to work harder to cut out the extraneous bits of the waveform (that is it’s job) but all that extra crap is just turned into heat. Laptop PSUs are small , so have less heat dissipation and likely aren’t built for this.

If it’s a sine-wave inverters and the generator is working properly then idk why it would matter.