There is a bug that is causing posts to be created without the user pressing the “Create” button.
I think this is happens when you switch between browser tabs, after opening a “These posts might be related” topic in a new tab.
This post was submitted without me clicking the “Create” button.
Make sure to report bugs like this one on the lemmy GitHub (after searching if someone else has already reported it of course). This way it’s much more likely the maintainers and other volunteers will see & fix it.