It was a similar (though more advanced) crack which led me to join this forum for advice.

At this size, it was already interfering with airflow. Basically doubled in size the next time I removed and reinserted the stem.

At that point I shipped it off for repairs (some sort of sealant and a band to reinforce) which set me back about $20, $25.
Worked fine ever since, although the tenon is no longer removable and I'm sure someday enough grime will build up the groove there that the pipe will explode into a thousand pieces.