I am able to reproduce this behaviour with <ALT>[wait]new tab[wait]<ret> in chromium-browser and firefox where I get 2 tabs reproducibly. With a gnome-terminal I get three lots of the paste buffer from <ALT>[wait]paste[wait]<ret>.
I am able to reproduce this behaviour with <ALT>[wait]new tab[wait]<ret> in chromium-browser and firefox where I get 2 tabs reproducibly. With a gnome-terminal I get three lots of the paste buffer from <ALT>[wait] paste[wait] <ret>.