> Cursor 'curSecondDefects' is getting created in the form's datasession

The culprit is that calling the form's method...

ThisForm.mExecuteSqlCommand(lcSql, 'curSecondDefects', '')

.. during the execution of mExecuteSqlCommand the form's datasession is current.

You need something like this (lots of stuff left out for brevity):

   loSession = create('session')
   Thisform.mExecSQL_DS( "select ..from..", loSession.DataSessionID

...
* in the form class:
function mExecSQL_DS(  cSQLCommand, nDataSessionID )
  local nSaveDataSessionID
  nSaveDataSessionID = set("datasession")
  set datasession to (m.nDataSessionID)

  sqlexec( ..., m.cSQLCommand, ... )

  set datasession to (m.nSaveDataSessionID)
  return
endfunc

Saving and restoring the current datasession is important because the current datasession on exit from a method will change the object's datasession. You possibly should consider a TRY .. FINALLY block or some equivalent around the code where the datasession is switched. Getting into the pros and cons of this is beyond the scope of this message!

Note, object methods switch datasession on entry. Standalone procedures/functions don't. So another approaach might be something like this:

* In globals.prg or whatever
function ExecSQL( oForm, cSQL )
  sqlexec( oForm.ConnectionHandle, m.cSQL )
endfunc

Again, plus all the stuff a generic function should have, return values, parameters, error handling