i have been comparing schema 'A' to schema 'B' and have been having some random procs being returned as being changed. We can see that there are only whitespace changes and that the ignore white space option is set.
Turning on the ignore comments option caused the changes to be ignored.
So consider a proc in a schema:
Create Procedure dbo.myproc
Select * from myTable;
if that exists on a database during schema compare all well and good.
Add spaces to the SELECT statement , still no change will be seen.
However insert a few TABs between "My Comment" and a spurious change will be seen,