I put my fixes in 2.1 but found another issue. I think line 3657 should be $insertdata like in master but not sure. Probably something you did so leaving it to you.

/mgz/survey/test/ls21/application/helpers/admin/import_helper.php(3658)

3646 $insertdata['qid']=$aQIDReplacements[$oldqid];
3647 switchMSSQLIdentityInsert('questions',true);
3648
3649 }
3650 if (isset($insertdata['type'])){
3651 $insertdata['tid'] = Question_types::model()->findByAttributes(array('legacy' => $insertdata['type']))->getAttribute('tid');
3652 //unset($insertdata['type']); //AJSL
3653 } else {
3654 $insertdata['tid'] = Question_types::model()->findByAttributes(array('class' => $insertdata['class']))->getAttribute('tid');
3655 unset($insertdata['class']);
3656 }
3657 if ($xssfilter)
3658 XSSFilterArray($insertdata);
3659 $newqid = Questions::model()->insertRecords($insertdata) or safeDie($clang->gT("Error").": Failed to insert data [4]<br />");
3660 if (!isset($aQIDReplacements[$oldqid]))

Fix committed to 2.1 branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&amp;id=10330

Could you verify the last patch is like it should be with the filters?

I review the filter for 21, but actually :
it's in /application/modules/CheckQuestion.php(431)

Ajs ?

This one is resolved : not same error : another bug ;)