This is because WinEdt runs TeX compilers in
errorstopmode, which means that the compilation hangs when an error occurres, waiting for the user's prompt.
You can type
x to terminate the compilation or
e to terminate the compilation and jump to the source of the error.
As far as I remember, WinEdt has always acted this way.
If you don't like this behavior, you can tell WinEdt to run TeX compilers in
To do that, go to Options -> Execution Modes and check the option "No Interaction" for the compilers you want:
If you want, you can press the button "Apply to All" to copy all the properties of the compiler to all the others.