On windows the keyboard shortcut to change keyboard layout is ctrl+shift (and ctrl+alt changes input language).
By default ctrl is used to strafe down in ship, and shift to slow it down. And they can be used together to get more controllable movement for example on planets.
For many people this shortcut isn't a problem because they don't have multiple languages/layouts configured. But in some for some languages (for example polish) there are 2 or more layouts. And many people aren't even aware of this windows feature. There is no notification, no message, no sound to notify of the change.
And in case of polish it changes from "Polish (programmers)" (which is the normal qwerty layout) to "Polish (214)" which among other things has Y and Z swapped.
This feature is enabled by default on windows, and many people eighter don't disable it, don't know how to disable it or aren't aware that it exists.