I'm having the same problem, at the moment I don't have regular insurance coverage (only winter storage coverage) so I haven't been able to try getting up to highway speed to see if it will reset.

Have you tried anything similar? Get up to highway speed when the spoiler is supposed to pop up, and see if it goes back to normal afterward?

I start the car weekly, but the spoiler pops up every time...and yes, the battery has died recently...darn trunk latch.