It seems that forecast dollars are “invisible” to a Lightning user until they momentarily switch from Lightning to the Forecast page in Classic, and then switch back to Lightning. 

I’m testing Lightning in a Sandbox.  Salesperson X has a deal projected to close next month for $25K.  The deal is in the Pipeline Forecast Category.  That salesperson goes to the Forecast tab, and sees $0 projected for next month.  User switches to Classic, goes to the Forecast page, and the user sees $25K in pipeline for next month. User switches back to Lightning, goes to the Forecast page, and now the Forecast page in Lightning is correct. 

Exactly the same experience with that user’s forecast manager.  In Lightning she initially sees nothing in the Pipeline for next month (even after hitting refresh).  She then switches to Classic and goes to the Forecast page, the dollars are there, then switches back to Lightning and the Forecast screen correctly reflects the dollars.

Using Collaborative Forecasts.  Is this expected in a Sandbox for some reason?  A known issue?