Question: It runs remotely in version 14.04 but not in version 18.04.
All graphics applications (gnome-todo, firefox etc) are lunched remotely via SSH.
However, when I run gnome-terminal remotely via SSH, it run in non-remote native gnome-desktop.

Answer: 
As steeldriver said in a comment above, new gnome-terminal instance behaves like some insipid Windows or Mac program; it only sends a message to the existing, running gnome-terminal to create a new window. 
To run gnome-terminal on a new client PC, use the --disable-factory or --app-id option.
This command works for me. I had to add the `--display` argument for Centos 7 (Newer gnome-terminal).

```
ssh -Y HOST bash -l -c gnome-terminal --display=${DISPLAY} < /dev/null > /dev/null  2>&1 &

```