This is normal. To prevent glass overheating and shattering, we have our wick holders extend 1/4" up from the base. This prevents very shallow wax pools overheating at the bottom of the jar and casing potentally dangerous hazards. We also recommend always burning candles on heat safe surfaces. Note that although there is some wax left in the bottom of the jar, at this point the fragrance oil is typically exhausted anyway - however you can scoop out the remainder for use in a wax warmer, if you have one!