Won’t fix is the answer to this problem 
original post:
Hi everyone,
Did anybody notice that the marking for “Development Only” in the context menu for nodes does not work?
I tested it with a new function (Ttt in the image) in an actor, but also other nodes like create widget and add to viewport that I execute on begin play.
To get the option in the right-click menu got to:
Editor Settings → General - Blueprint Editor Settings → Experimental > Advanced
and enable: Allow Explicit Impure Node Disabling
I read that there is a bug in UE5, that lets the editor actually package a develeopment build, even though everything is set to shipping.
I tried Platfroms->Windows->Package with everything set to shipping in the Project Settings and the in the sub-menu where I start the packaging process.
I tried Legacy Project Launcher, the new Project Launcher with all settings set to shipping, follwing the this video tutorial:
I can not open the console and Prints String nodes don’t appear on the screen, so I guess I actually have a shipping build.
Yet, the “Develompent Only” marked nodes still execute.