[BUG] [Video]Blueprints are crashing my engine no matter what i do

So i have no idea what has caused this as it was working just fine for many days up until last night when i tried to create a variable it crashed. then i loaded it back up tried to delete the variable or lines of nodes and it crashed again, Now no matter what i do in these 3 similar blueprints the engine crashes. these 3 seem to be the only ones it crashes in but i am not sure of that because i havent tested every single blueprint graph i have that is apart of my project. i uninstalled version 4.16 and reinstalled it cause i thought it would fix this but it didnt , i made a new blueprint actor with the same nodes as the 2 of them and it crashes. so i dont know what is going on

here is the video link - YouTube

anyone have an answer or a possible solution?