Please try to factory reset your keyboard by holding fn + Z +J for 4 seconds.
If the problem persists, please try flashing your keyboard to the latest firmware (Keychron firmware).
Note: please download the right firmware that matches your keyboard model. Be careful that if your keyboard model belongs to the ISO version (like UK K3v2, DE K8) or JIS version (like Japan JIS K8), you should download the corresponding ISO firmware to update your keyboard because regular US layout keyboard firmware is not compatible with any ISO layout or JIS layout keyboards.