A general comment (heh) here. This is not a bug and not easily fixed. Line comments are their own top level element distinct from paragraphs. If you need something that fits in a paragraph you can use @@comment:@@ at the start of a line.
I agree that it is annoying, but Org line comment syntax also only works if it starts the line, so the behavior diverges from traditional code comments. It may make sense to update the docs to call them "line comments" instead of just comments. One area where we could almost certainly do better is in how line comments break up the flow of text. I'm not sure there will ultimately be much we can do about it, but it is worth investigating. Best, Tom