It's common, you are burning a little too hot and starting to char the bowl. Leave it as is and smoke a little slower/cooler, pay attention to the heat, especially when breaking in a pipe. It's ok to let the pipe go out from time to time. When the pipe goes out use your pipe pick and empty out the smoked ash portion, not the unsmoked tobacco, even out unsmoked tobacco and relight. Continue to smoke the pipe to build up a small layer of cake, which is more heat resistant.