title: Missing columns in dataframe(spark-2.4)
body: <p>I have appended two dataframes to some s3 location and while reading it one of the columns in output df is missing. 
  The same piece of code is working completely fine in spark-2.0 but in spark-2.4 column is missing.</p>
  
  <p>There is nothing change in code.I'm just trying the same code in two different versions of spark.</p>