Unknown Formula =[@[Duedate]]

Typically, you'd see something like this:

=TableName[@[Due Date]]

Where:

TableName is the name of the table

If no table name is present:

=[@[Due Date]]

That means the formula is in a cell that is within the table itself.

The outer [ ] mean everything within them belongs to the table named TableName.

The @ sign means "this row". If the formula is entered in cell X10 then it refers to the cell in the Due Date column on row 10.

The inner [ ] refer to the column range headed by Due Date.

If you want to see what the formulas look like in A1 reference style then:

Select any cell within the table
Right click>Table>Convert to range

Select the cell that contains the formula. You might see something like this:

=Sheet1!$B6

Now, on the main menu bar click Undo to get the table reformatted back to a table!

You're welcome. Thanks for the feedback!