While charging the battery [8] R popped up where it shows the gear

My radiator got busted a while back and I just got a chance to fix it today. I got everything put back on and we went to charge the battery. The battery is brand new , I got it about six months ago. As we were trying to charge it there is a ticking sound coming from underneath my steering wheel and when I looked where it would tell me what gear I am in it read “ [8]R” on it even though it was off and does not show anything there usually whenever the car is turned off. That went away and so did the ticking but the ticking started back by itself then stopped again. I cannot find anything about this anywhere .