For me the double-click thing eventually went away, but the the batteries started to have very short life instead. I consider the G7 Logitechs black cheep in it's family.

Logitech support commonly recommends a potential solution for the double click issue - essentially they say that static charge builds up in the mouse over time.

Gadget reviewer Doug Aamoth has few regrets in life. One of them is attempting to fix a Logitech G700 mouse where the left mouse button periodically double clicks when he means it to single click.

If you are experiencing a repetitive cycle of the double-clicking mouse, check this article to see the best possible solution for this problem.