This is known as key rollover, see: https://en.wikipedia.org/wiki/Rollover_(key) https://en.wikipedia.org/wiki/Rollover_(key) It is a result of the matrix wiri

This is known as key rollover, see: https://en.wikipedia.org/wiki/Rollover_(key) https://en.wikipedia.org/wiki/Rollover_(key) It is a result of the matrix wiring of the keys, though more expensive keyboards will have them wired individually, mitigating this issue.