open -a Gimp has stopped working

[ryofurue]

Upon upgrading to Gimp 2.10 (through "brew cask install gimp"), the open command has stopped working on Gimp.

Before the upgrade,

$ open -a Gimp

used to open gimp. Now Gimp is installed as /Applications/GIMP-2.10.app , but none of

$ open -a GIMP-2.10
$ open -a Gimp-2.10
$ open -a GIMP
$ open -a Gimp
$ open -a gimp

opens Gimp.  I haven't seen the same problem on other applications.  Is this a problem of Gimp installation on Mac ?

I use macOS High Sierra.