Datatable - Async data https://mdbootstrap.com/docs/standard/data/datatables/#docsTabsOverview

In the example provided you use "const columns" variable for the columns, and reference it like this:

  const asyncTable = new mdb.Datatable(
     document.getElementById('datatable'),
     { columns, },  <-----------note parameter name only
     { loading: true }
  );

I changed the variable name to "columns_set1" because I had multiple tables. However I didn't realise that by changing the column name I had to reference it differently.

  const asyncTable = new mdb.Datatable(
     document.getElementById('datatable'),
     { columns_set1, },  <-----this is wrong
     { columns:  columns_set1, },  <-----this is correct

     { loading: true }
  );

It might be good to write in the documentation that if the column parameter name is not "column" then the descriptor "columns: " is required beforehand.

Or it was me just being dumb :)