I'm playing on PC, Steam, build 1.5.72378 . The prompt to bribe bobbies seems to appear or not appear almost randomly. There doesn't seem to be any reason as to when it does or does not appear.
When the prompt does appear, bribing doesn't work. Most of the time when I attempt a bribe, things pause as if an animation is playing (I can't move for several seconds), and the Scotch (or other alcohol) disappears from my inventory, but nothing else changes. The bobby doesn't act as though he's consumed any alcohol afterwards. Occasionally I'll find a bobby where the animation actually plays and he'll become intoxicated, but the majority of the time, I'm just losing scotch and not seeing any change.