Sometimes Kemosabe, the coil gets pushed off to the side. look
through it with light behind it and see the coil at the bottom. If it appears centered,in the tube, that's not the problem. If its off to the side, it will always taste funny/off/burnt. No fix I've found. Sorry.
now if you are certain you have saturated the filler, initially to the point you got a drip or two out the bottom, I have one more thing you can try.
Try pushing the filler down a little with a regular sized straw. the straw allows you to push down on the filler evenly without disrupting the center tube. You can also try packing the filler down a little by tapping it on your palm, threads to palm, just like you were packing a pack of smokes. This will make sure the filler is down there properly and able to wick to the coil.
The horizontal
coils are not wrapped in the filler like the old vertical style so you can actually pull up and push down the filler without disrupting the coil. But contact is still important.
I often adjust airflow issues by tapping the wicking up or down.
That's all the tricks I got. I'm currently suffering the taste from a bad one right now, Toss it and move on is all you can do sometimes.