Layers not showing base layer objects, despite the show icon being selected and visibility being locked

Hi e-Learning Heroes,

I have had this problem for a while now, where the base layer objects do not show when I create a new layer. I have tried locking/ unlocking the visibility of the base layer,  both while on the base layer and in the timeline of the newly created layer (see attached screenshot). Subsequently, I have been copying and pasting the objects from the base layer to the other layers, but this is becoming really inefficient. 

I have also tried re-downloading/ reinstalling, as suggested in the How to Fix Unexpected or Erratic Behaviour article. I have also had a fiddle with the Feedback Master view, but still nothing. 

Any help would be greatly appreciated!!