That's a tough one. Clear can sometimes change the hue of the underlying color. Gloss clears tend to richen the color while satin or flat clears will wash it out a bit. Can you describe the "random patterns" a bit more. Foggier areas maybe? You may have just gotten a bad can of clear too. If you have any left, spray it on a piece of clean metal or the like. How does it react then? A word of advice on all satin clears - shake the can to within an inch of it's life. The flattening agent that is added to clear ( or color for that matter ) tends to settle out rather quickly. If the can has been on the store shelf for a while, the agent can become a rock in the bottom of the can. If it's not dispersed in the clear really well, varying degrees of sheen could result while using the can.

Regards,
Dan