Why does Windows command prompt stalls until a key is pressed when executing long batch files or programs
edit the settings on the command shell that you've opened up its been set to quick edit mode which you don't want in this case.
I have seen this with Powershell several times when focus was removed from the Powershell window. Perhaps that's what's happening here as well? Every time it happened things would spring back to life after the window re-gained focus and I hit Enter.