Terminal autocompletion freezes the UI on a fresh Ubuntu

I’ve just installed Ubuntu 18.04 on a pretty powerful desktop.

When I open the terminal and type

ls /

The cursor stops blinking and the whole UI is frozen. Only the mouse can move. It lasts between 0,5s and 3s depending on the moment.

I tried to install zsh. It has the exact same behavior than bash.

Following this this superuser question I tried the set -vx thing. It stills freeze, but nothing more on my console about it.