Hi Nickie
It still could be air cavities, did you tap the glass to even the air?
Also did you leave the candle to stand overnight before burning, I have read that candles need time to settle and harden this can cause
the wick to burn too fast.
I also read that if the wick is too small this will cause it to burn quick, priming the wick helps too.
I am going to try container ones very shortly but I am off with a bad arm at mo so I am making a few cards as this is nice and gentle
Karen