Adding Items from Lists to Dictionaries in Apple Shortcuts

I have this Shortcut which queries a Notion database, then fetches the IDs and titles of pages from the database and turns them into key : value pairs.

I want to add those key : value pairs to the dictionary shown at the top of the screenshot. The problem is, even though I can see that I'm adding to the dictionary inside the Repeat With Each Item loop -

When I check the contents of my Categories dictionary at the end of the Shortcut, those entries haven't been saved.

I have seen this answer, which appears to solve the same problem. But when I implement it and then check the contents of the variable inside the loop, nothing is even being set here.

I'd be very grateful for any pointers here.

I figured out the problem - I needed to set the dictionary as a variable outside the loop -

And then I can update the dictionary inside the loop -

I don't know why that works but it does ¯\(ツ)/¯