With a simple dataFrame that look like this

The following code

fig = px.timeline(df, 
              x_start="Target Date Start", 
              x_end="Target Date End", 
              y="Initiative", 
              color="Status Bin", 
              facet_row="Project Key",
              template="plotly_white") 

Generates a graph that does not adjust based on facet row. I would expect only initiatives associated with a given project key to show in the y marks, but instead all initiatives are shown: