There were some spacing changes in the v.1.3.7 release, but nothing that should create a long gap (I don’t think). A bit more information will help others help you here.
What Obsidian version are you using? What OS? …things like that. You already mentioned it’s the same using different themes; that’s good to know. And a screen shot or two as well: maybe of the gap you see in the editor and something from the inspector to get an idea of where the space is coming from like this:
