It seems like a menu entry was forgotten in.
In the Software Selection / tasksel section of the text installer in the netinstall image, in addition to "Triquel desktop environment" there is "Triskel desktop environment." The latter should be removed.
Triskel environment is the KDE desktop flavour of Trisquel, which for the time being is not a mainline offering but netinstall is provided as a convenience for existing users.
Perhaps I have missed some important discussion, and also, I'm not a developer, but as a KDE user, I don't know why they would remove the option to install KDE in tasksel.
Someone, please provide more information.
Best regards, ADFENO.
Have a nice day.