mrkgnao: Not necessarily.
On day #1 of the sale, Age of Wonders 3 Deluxe cost 40c more than it does now when it appears on the Flash sales.
apehater: oh, thats interesting. any ideas why this discount roulette?
My guess is a rounding bug. The first day discount was rounded down to 66%, now it's rounded up to 67%.
Generally speaking, GOG is very dependable. If there is a potential for a bug, you can be pretty certain that it will appear on GOG at some point.