This morning I was getting ready for my uber driving shift and something happened that never happened before. I started the engine to warm up, exited my car, came back after 5 mins and I was locked out while the car was running! Luckily I was at home and had a spare set of keys, but the spare fob wouldnt unlock the car, I had to manually turn the knob to get in. I thought it was impossible for this to happen if the key was in the ignition? I did notice when I cranked it the overhead dome light dimmed lower. I hope this isnt an alternator issue?