Question about gis addon and knife tool

Hullo, I´ve been learning blender for about a year now, and I just found out that I can not use the knife tool once I have a gis terrain, like instead of cutting and splitting faces it deletes the faces, now my question is if this something from the add on? or is it a bug? did anyone ever seen this and is there a way to circumvent it? thanks in advance

Which addon are you using?
Can you apply modifiers / convert to mesh / make real?
Can you share a .blend file? - (just drag and drop)

hello, so, the add on is gis (BlenderGIS), and yes I can apply and do almost everything, like I´m still modeling the houses on top of the terrain, just without the knife. and here is exemple file of a file with this problem.
here is the sample file. it´s a blend file with all gis textures. 126 meg

thank you SterlingRoth.