MacBook :: Trackpad Clicks Not Registering Consistently - Especially After Wake Or Boot

My MacBook had the trackpad clicks-not-registering problem that was cleared up by the Trackpad Firmware Update in November. Unfortunately, a variant of that problem seems to have surfaced. When waking from sleep or on boot, roughly half of the trackpad's clicks won't register, forcing me to click two or more times to start an app or read mail. After five or ten minutes, the problem seems to abate. I still "lose" clicks now and then, but not as often. Note that other trackpad functions seem unaffected when this happens.

I've tried resetting the SMC (no effect) and PRAM. Resetting PRAM cleared up the problem but only briefly, and now it's recurring.

I took the MacBook to the Genius Bar and the Genius suggested I use "tap to click" instead, but while that works, I'm a sloppy clicker and found that setting irritating.