I have a strange problem and I've never encountered before. Recently, I notice even when my charger is connected to my MacBook Pro, it sometimes shows that the mac is running on battery. I can wiggle the magnetic connector (or hold it tighter) and it'll "connect" for a few seconds or minutes only to revert back to battery. Sometimes, rebooting helps this but it appears to revert back to it's old ways in a day or two. Any suggestions?