This has been happening intermittently for a while now.
Problem: I enter a Text Literal and press enter to exit the edit mode. All looks fine.
Then I’d go back to the User Interface, (screen layout). Still, everything is fine. Now returning to the Logic block, I just created and the text literal that I just entered is gone. Like this.
Solution: Seems just pressing Enter is not enough to save the Text Literal to the server. One must ALSO click on any parent block as well. Then the Text Literal is saved.