I first reported this problem to the Mintty project at GitHub.  With their help, I was able to debug the issue to the call to forkpty.  I installed tmux and found it also hangs the exact same way.  My guess is any process which makes this fork call will hang in a similar way. Rather than copy/paste the thread, I'd rather just refer you to there : https://github.com/mintty/mintty/issues/960

I will also direct link to the strace log I made which includes my comment showing where the hang happens:
https://github.com/mintty/mintty/files/4136651/mintty.strace.log (Line 718 is the hanging point.)

Also Windows 10's analyze wait chain function in TaskManager shows the process waiting for Network I/O, but we see no evidence of network activity. https://i.imgur.com/Uiw9laH.png

I haven't seen any other windows applications hang thusly, so I'm at a loss for what I've done to my windows system to have caused this. Otherwise, I'd expect others to share my pain.  Any ideas?