I bought the last month 2 starter sets with nautilus mini so I can go from one e-liquid to another.and I have always a battery that is fully charged. Last week I lost the O-ring on the base of my first nautilus drip tip. Today I have the problem with the second one. Result: the drip tips are not keeping on the nautilus as the o-ring is missing. This has happened twice in one week! Is this normal and what is the cause? I have looked on the website and you cannot order the little O-rings separatly. So I ordered the drip tips. But at this paste I better order an entire box. Thanks in advance for the suggestion.