Fundraiser archive page = Error 404

This worked for the last 25h and now it just throws a 404.
> I have uninstalled and deleted the plugin
> I have deactivated other plugins
> I have changed the slug/path
> I have deleted all fundraiser
> I have created new fundraiser
Nothing fixed the 404 for this one page.

Then I remembered that I changed the permalink structure yesterday and changed it back. 404 is gone.

I am pretty sure this was not mention anywhere in the manual as "never do this". Also not sure if this is supposed to be that way.

Could someone please explain me the logic behind this, so I understand it. Seems like the plugin only works with the permalink structure set to "/%postname%/" or standard.

Thanks and cheers, Alex