Vodka evaporating

I have two bottles of Meili vodka autographed by Jason Mamoa. So I did not have any intentions of using these 🤣. But I noticed one of the bottles appear to be evaporating- not a ton but noticeably different from the other bottle which has not seemed to evaporate at all.

I’ve had these for approximately a year now. Is there anything I can do to try to stop or slow the evaporation? I should I just pop it open and drink it? 🤣