You're not crazy. I did a experiement with this tobacco juice I make. I use glass bottles and I made up a 15 ml bottle of it. I have not touched it and noone else has either. After just a couple of weeks of sitting it is only half full now. No leaks ..So it can happen.
That is why I don't make my juice in bulk anymore. Just what I need for a week or 2.
Whaaaa?
Something is wrong if half of your bottle is evaporating in 2 weeks. I've left out 30ml glass bottles both capped and uncapped but never noticed any evaporation, even after several weeks. Maybe if you are using a lot of flavoring that contains alcohol or there is a high percentage of water, but otherwise methinks you have a closet nipper.