export - exporting table in to a drive from Google earth engine returns blank rows

I am trying to find the mean precipitation of a watershed. When I print the feature collection BasinMean, I can see the mean precipitation in the console. A lot of them are zeros but the first two rows have non-zero precipitation.

When I export the table in to a drive, I expect a CSV file which is a timeseries with 3 columns - Station, date(timestamp) and mean precipitation. However, with the below code, the generated CSV has empty cells for mean precipitation. Any idea why the export function does not work?

Link to the workspace : https://code.earthengine.google.co.in/7f21f81224e88bed21e2db64fb7fda30

// Filter the image colelction for a certain timeframe

var filtered = Chirps_daily.filterDate('1981-01-01', '2016-12-31');

// Display the basin
Map.addLayer(Basin,{color:"#008080"},"Basin");
print(Basin,"Basin");

// Load the first image of the collection
var Chirps_first = ee.Image(filtered.first());
print(Chirps_first,'Chirps_first');


// Load the scale of the chirps image
var Chirp_scale = Chirps_first.projection().nominalScale();


var BasinMean = Basin.map(function(f) {
    return filtered.map(function(i) {
       var mean = i.reduceRegion({
       geometry: f.geometry(),
       reducer: ee.Reducer.mean(),
    });

    return f.setMulti(mean).set({date: i.date()})
  })
})

// flatten
BasinMean = BasinMean.flatten()
print(BasinMean.limit(20))

Export.table.toDrive({
  collection:BasinMean.limit(20),

  folder: "Google EE results",
  selectors:(["Station","date","precipitation"]),
  });