Compose key sequence changes the cursor permanently
Using any compose sequences will change the cursor permanently. It's a serious visual bug and it will hide whatever is behind the cursor.
gnome-console version 45.0-1
Also, this isn't an issue in gnome-terminal
Here is a video of it. (The video is a side by side comparison between gnome-console and alacritty, which is not relevant here)
In the video, I tried to type "script a" ɑ (vs a) using compose
s
a