Ok, sorry for the last answer.... I still can not imagine your scene.
1- If you are using rigidbodies to make scenary collision objects, probably this invisible objects fall down to the infinite.y position by gravity effect. Put a sprite inside the rigidbodies to test that And if the objects fall down, change "mode" to static or replace with staticbody2D. (put the sprite inside- this is important, if rigitbody is child of any visible object, this object can stay at the place and the rigidbody down, and you don´t notice that)
2-If you are using a Area2D to stop physics movement think that this is not the aim for this node. You should replace the area by a Staticbody2D and it should work. You can put several collisionpolygons inside and if is not "trigger", it stops kinematicmovement (if layer mask is correct)