Hello There, That was three months ago!
The way to visualize that sort of thing is to temporarily revert it. This can easily be done with JOSM but I see you use the iD editor which won't allow for reverting.

I reverted the changeset to see how it was before your edit. You had inadvertently dragged 5 or 6 nodes out of place. Including a node from the building Way: 782816185, the node was dragged across the building outline making for a self-intersection of an area outline. I've saved a screenshot of it to Google here:- https://docs.google.com/document/d/14o4IcueIcCIA9NrY7bVODKr0juhDlR386V-Z2KqMI54/edit
I think you should be able to see it, please let me know yes or no as I've not used Google like this before.

Regards Bernard.