In comparison to the right button, the left button makes a strange sound and feels different when clicking.
Both buttons should have the same actuation feedback. If one sound is different from the other, it is possible due to the manufacturing tolerance, or our adjustment in our production as to make a consistent clicking feeling (consistent sound is not our main focus).
If it doesn't impact your feeling in-game, you don't need to worry about it, but if it impacts you in-game, or the sound is too strange, there may be a problem with the switch or shell. If the product is still within the warranty period, please contact us (ZOWIE website/Support/Contact/RMA).