I think GCD nailed it - I think it's simply you're getting the jighead too hot before you dip, and always dip in the powder with the eye up - don't make the eye the lowest point - shoved through to the bottom of yor dip. Some jig designs make this hard, but you can angle the jig or shift the powder in the container so it isn't on the bottom.
I had the same problems at first, but then I started using an inexpensive heat gun, and counting the exact time needed to heat the jighead (held by the hook bend by locking hemostats).
I found if I heated the jighead for only a second on each side for every 1/16th ounce, it was enough to get the powder to cover - looking exactly like that picture he posted. Then into the oven for curing - no closed eyes. For small batches or just testing colors or for personal use I just heat and dip, tap the excess off, then turn over the heat gun for another few seconds and I'm done.
Using this method I don't need a fluid bed or any other gadget. Your torch will probably heat a jig faster than my heat gun, so you may only need a second or two on each side for all but the biggest jigs.