🚀 go-pugleaf

It sounds like when you applied the condition you applied it to the text but forgot to include the end-of-paragraph mark of the paragraph. If you want to have show/hide capabilities on the entire paragraph (including its number) then you have to conditionalise the entire paragraph, including its end-of-paragraph mark. If the end-of-paragraph mark is visible then its number will be, too, and it will also take up a line of space.

And make sure you turn on the View > Text Symbols so you can see the end-of-paragraph marks (unless you enjoy driving while blindfolded).

That's not to say that you should always conditionalise the end-of-paragraph marks. I use conditional text to produce documents in different languages from single-source masters, and I don't conditionalise the end-of-paragraph marks because I want all languages to use the same paragraphs, same paragraph numbers, and same cross-reference markers.

What you should conditionalise depends on what you want. In your case it looks like an error in applying the condition, possibly caused by having the text symbols turned off so you couldn't see where the condition stopped.