It can be as jon_slider pointed out with the rubber seal. While the momentary switch can work fine, it’s not properly centered. Every time you push the titanium button it is only hitting on one side of the button because the switch is mounted out of center on the FET switch pcb. That’s why it can feel a little funky sometimes, its only a straight down action if you press where the switch s located. Pushing from any other location makes the button run down a little side ways and the action doesn’t feel as good.

Borrowed pic from here. Drop.com $20 off - Lumintop Copper/Brass Tool for $10 - Discount not available as of 12/10/19 - #204 by argolite