Tri Floors invis glitch also building is iffy

Attached are pics of issues

Image of invis triangle floors from underneath but ontop is ok

Image of how the building system is iffy, facing mainly to the right yet wants to place floor on far left, also issues with this with roofs.

Thanks guys

Same Issue was already stated at following thread:
Triangle Floor Bug

And to add some Information: ist only with twig triangles … Wood, Stone and Metal is okay