Static Objects and and terrain detail turn white upon opening scene?

Hi guys, been having this issue since I switched to Deferred lighting. Every other time I load a previously saved scene in Unity 5.1.2 all static objects and and terrain detail turn white while the terrain itself turns black. To fix it, I have to go into the player settings and toggle VR on/off to "reload all graphics objects". All my and materials are in the correct locations and it doesn't seem as though the textures are missing anyway. What could be causing this? Screenshots of issue -

before toggling VR

After toggling

Any help appreciated! :)