If your mouse is using optical Raesha switches such as the X2V2, X2H, X2A, and X2 Bruce Lee Edition, it is likely that your mouse has a defective Raesha switch.
A defective Raesha switch will make a second click feeling and sound after the actuation point, in the post-travel or in the release. This click is unintended, and will not create an input in your computer.
The switch is defective and needs to be replaced.
Optical Raesha switches are hot-swappable, and replacing them is easy. However, please only do so if your warranty is no longer valid, as doing so may void your warranty.
To remove them, you just need to pinch the tabs under the switches to release them. You can also remove them from the top by pulling them up while moving them around under they come out, although this may break them, so only do this if it is defective.
You can check if the switch is defective by pressing directly on the micro-switch and checking if you hear two click sounds.