Why does the side of my candle look odd, like there is air inside?Updated 18 days ago

Some candles that are made in transparent glass can look like there is an air or water bubble between the wax and the glass. This is just a visual effect from the wax pulling away from the glass a tiny fraction due to environmental factors during and after their creation which can be unavoidable at times. 

Glass adhesion does not affect the burning performance of your candle and is just an aesthetic issue that is the bane of chandlers who choose to use transparent glass for their candle vessels.