I’ve had that happen as well, I don’t know how to fix the issue you’re talking about (I usually just made a cell elsewhere and dragged it below the wonky one, and cells added after that will be normal). Easiest go around is to paste and match style, but that sometimes isn’t a good solution.

Hopefully someone more knowledgeable can field your question so I know too!

Thinking about it, it’s probably a ruler function where the ruler stops are being copied, and Notebook assumes the next cell should retain the same stops to prevent you from having to recreate every cell.

Best bet is paste and match style.

I think I know what is happening. Each paragraph in a Notebook has a ruler associated with it. Choose Ruler from the View menu to see the margins that are set for the current paragraph.

The default ruler in a Notebook has a flexible right margin. That is, as you resize the window, the right margin automatically aligns with the right side of the window.

If you make a manual change to a ruler, then its settings become fixed and do not change dynamically when the window changes. The ruler for the cells you see a fixed (or hanging) margin for are probably of this nature. You can set that by hand, but in your case I see that you copied and pasted some formatted text from PowerPoint where the ruler information is included on the clipboard.

The easiest way to remove the formatting is to select the paragraph and use the Plain command from the Font submenu of the Format menu.

You can also use the Copy Ruler and Paste Ruler command from the Copy and Paste submenus of the Edit menu to do this as well.