After switching to 'Meld for Mac' from download instead of from homebrew, I saw problem again.
The problem is related how the app is closed. If you use the Menu option, the saved state is removed cleaning. If you close using the window close (read circle), the saved state remains. Somehow, when this there, the application will not open from command line. Sometimes it will open, but you need to manually switch to the Meld application from the tool bar.
To work around I added /Applications/Meld.app/Contents/MacOS/meld.wrapper.sh: