If you drink during your window then it counts the same as any other calories. It's fine. Just account for it. Not eating at your usual time and waiting to eat/drink when you're out on the town or whatever the case may be is a totally valid strategy. The key is to be flexible.
The 'benefits' of fasting come from lowering your insulin level, which drops depending on the type of diet you eat (lower carb is better), how frequently you eat, if you are exercising, and where you are at on your weight loss journey. Intermittent fasting drops the frequency of meals and adds a period of 'rest' for the body so that insulin levels drop, allowing your body to access fat stores. It's nearly impossible for the body to utilize existing bodyfat when your insulin levels are high.
If you have a bad week diet wise or just feel up to it you can always find a day and not eat that entire day, fasting from one meal to the next. So, for example, Saturday dinner to Monday whenever you usually eat your first meal. In addition to feeling good, you'll bank that day of calories with no real downside. Your metabolism won't drop, you won't lose muscle, you won't keel over and die.