A number of keys conflict with the spacebar:
- While the ASD keys are held down, the Spacebar cannot be pressed.
- Pressing ASD while Spacebar is held down will cause Space to be released while any of the ASD keys are held down.
- Briefly tested, the other keys that similarly conflict with the Spacebar are 12345 (above QWERTY), Tab, Q and E.
Also at random, random keys will stop working until the keyboard is replugged.
Tried uninstalling the drivers from Device Manager, installed Synapse 2.0 (Why am I forced to login to configure my keyboard?), and neither solved the problem.