I'm aware that there are many versions of the first depth you'd go through, but for this particular session the candles made to open gates appeared to have already been lit despite me not touching the embers. I thought those candles were intended to be lit, but the game behaved otherwise since the gate was still closed and the Grimalkins were able to follow me through the blue light.
I'm not sure if this image will help, but here it is:
http://steamcommunity.com/id/Ambrosia_Delacroix/screenshot/5057666562402...
This has only happened to me once out of many replays though, so I'm not sure what I could've done to trigger this.
Did you try to still light it?
The gate was closed, grimalkin could walk by them.... the game didnt consider them as lit.