In my experience 30 watts is a little warm for those coils, or would be for me, as I usually vape at 25 watts with the .5 ohm coils. The new vertical coils are rated higher I believe (I rarely use the factory coils in my subtanks anymore).
The only advice I can think of is to take the coil out and make certain the oring is on the bottom of the coil head, make certain the bottom part of the tank where the air holes are is clean (qtip, paper towel). If the coil is already "wet" you won't need to prime it again. Just make sure it's firmly seated in the bottom (finger tight, not wrench tight). Turn the power down to 20 watts and take a hit, bump it up a little and try again. If you have a flooded coil and too much power it will spit.
Good luck.