Not strange at all, really. Bad batteries and bad connections at the battery both cause WEIRD stuff to happen to these cars. If your spoiler develops a mind of it's own, or your BAS light acts up, or if your AM/FM won't turn off, or wont turn on - consider the battery and terminal connections.

You might consider the age of the battery - if it is getting up there in years, be wise and replace it. I've been on this forum over 4 years, and I have lost count of the number of owners who have paid hundreds of dollars to dealers in diagnostic fees - only to find that the battery was on edge the whole time. One guy had his battery fail a few days out of warranty.

Personally, I buy the cheapest battery that meets the CCA specs for the car. I then replace it every three years - that means, the first week of January, 2014, I'm due to buy a battery. I once was towed (cost of $110) and paid $90 in diagnostic fees - only to find I had a bad battery. I will N E V E R allow THAT to happen again.