So definitively something on my end. I've googled around but the common issues like “draw hulls only” enabled does not solve it for me. Reverting the display settings is also no fix for me.
I'm using 17.5.425 and also qLib (don't know if this is relevant).
i also missing heightfield and not displayed on the viewport. in my case i accidentally viewing in WIREFRAME, after switch to SMOOTH SHADED its appear again using 18.5