This issue is due to the fact that the Z operates as a US QWERTY device, and windows does not support multiple devices with different keyboard layouts correctly.  So if you are using a non US QWERTY keyboard, some of the Z's outputs will be modified by windows to match your keyboard layout.

Hopefully we can add other keyboard layout options for the Z in a firmware or driver update. But for now the only solution is to keep the conversion in mind when you are setting up your mappings.

So when you want to send a key that has a different position on a QWERTY keyboard, look at the position of the key you want to output on your keyboard, then output the QWERTY key in this position instead (adding a Shift Modifier when required). When windows receives this key it will then translate it back into the key you wanted.