The object you see in the console is a snapshot of the object at a particular point in time – the time when you logged it. When you expand the object, it will evaluate the properties again.
In the example below, I have created an object with two array properties. I logged it the console, and then I added a third property, c
to it.
Only the first two properties are showing still, even though I just added a third property. After expanding the object in the console, I can see the third one. It is the latest state of the object.
If you hover over the little blue i
icon, it explains what it has done:
Value below was evaluated just now.