I've noticed a recent change with the Notion App for Mac that appears to be a bug, but maybe it's not. When I add a Web Bookmark to a page, I'll oftentimes add an additional space below the bookmark in case I need to add a label above any new bookmarks further down the page. Lately, I am experiencing where Notion outrights removes the newly added extra space right after I have added it. It doesn't happen 100% of the time, but it happens a lot, which is becoming frustrating. The app maybe 1 month or longer never did this. Is this by default now?
Notion don't add blocks above or below the bookmarks, just confirm you don't have any blocks above or below before pasting your URLs, because if you do, the empty blocks stay there.
And just in case it is actually a problem in an old Mac app version, update it to the latest version (2.2.1), where the problem is not present.