The Editor create/destroy objects when initializing Worlds… Some object might be created, but is referenced by nothing then it’s GCed.
And Editor might initialize Worlds multiple times, depends on the tools you’re using to place actors, edit an asset, etc.
Usually you will see PostLoad() called only once on every Editor startup, but PostInitProperties() will be called on Editor launch and also execute every time you click the “Play()” button and on packaged game.
(because the ‘CDO’ will always be created on Editor launch and its Constructor is executed every time for each class)