I have two formula fields. 
The first one is "start date" which is always TODAY()

The second one is "End Date" which is TODAY()+3

When I open the record on salesforce, the "start date" field shows as blank but the "end date" is working perfectly fine and is showing as the current date plus 3 days. 

When I tested the API to pull info from salesforce, the start date is None but the end date is working just fine. 

I solved the issue for the "start date" field by changing the formula from TODAY() to TODAY() + 0

I'm not sure what's going on and why this is happening. Does anyone know ?