To be exact, it's not just the G100s.
The Omron switches that people love so much have a relatively low spring preload compared to other switches, the reason for their soft clicks.
To achieving this kind of low preload without having entirely defective switches require very good QA, which is why Logitech sources from Omron for their high quality.
And because of their consistency, Logitech is able to set the lowest debounce latency among all brands in their mice.
The problem arises when fatigue/creep over time is considered. The preload effectively provides breathing room for when the leaf switch loses some of its shape over time.
With a lower preload the switch becomes much more sensitive to this effect. It becomes too loose and will not have sufficient tension to hold the contact points together firmly
On top of that, Logitech sets the debounce time so low as to leave no room for the change in behavior.
You can fix this problem by increasing the spring preload slightly. The click will be somewhat harder but more responsive, and it won't double click or lose its tactility entirely over time.
Edited by daniel0731ex - 9/27/15 at 3:03pm