Can't read from stdin in debugger

just updated QT Creator to 4.13.0 and now I can't read from stdin while I'm in the debugger.

A few details...

• I am writing C++, but using C stdio library. (for historical reasons)
• I am using qt 15.5.0 toolchain in c++11 mode.
• I am using the 'Run from Terminal' debugger option.

Problem: Type as I might, when my code goes into fgets it never returns. (See sample program.) 
#include <stdio.h>

int main()
{ 
    char buf[1024];
    if (fgets(buf,1024, stdin)) // In debugger, this call never returns!
   

    return 0;
} 

Note: When I run this outside of the debugger - no problems.