https://wiki.ubuntu.com/Apport

It intentionally acts as an intercept for such things, so that core dumps can be nicely packaged up and sent to maintainers in a GUI-friendly way so maintainers can get valuable debugging information even from non-tech-savvy users. If you're running something on the terminal, it won't be intercepted and the core dump will be put in the working directory of the binary, but if you executed it through the GUI it will.

Assuming, of course, you turn crash interception on- it's off by default since it might contain sensitive info. Apport itself is always on and running to handle Ubuntu errors, but the crash interception needs enabled.