Happened on Chrome OS R73-115588.0.0.

1. Crostini installed and had the Terminator app outside of the Linux Apps folder.
2. Right-clicked on Terminal and did an Uninstall. 
3. The Linux Apps folder disappeared...but Terminator did not. 
4. Clicked on Terminator...which gave the spinner for awhile and that installed Crostini in the background.
5. Clicking on Terminator again doesn't do anything (it briefly shows the spinner and then goes away)....but I can verify in crosh that termina is running now; and in Settings it gives me the 'Turn On' Linux option.