There's three or four bugs related to Call Pickup in CCM 4.1.3, as well as Auto Call Pickup.
I tried SR1, but it didn't fix all of the call pickup problems. I got TAC to send me ES13 for 4.1.3; that fixed all of them.
You can try SR1 first, that isn't going to hurt any. Then if it doesn't fix it, open up a TAC case and see if you can get ES13.
TMH