TSNgaihte,
The warning from PA is indicating that some style settings for the document being created result in these paragraphs (mt2, mt1, is, iot) occupying an amount of vertical space which is NOT a multiple of your current body text leading. As a possible example: Body text leading is set to 13pt and mt1 has space before of 9pt and space after of 3pt.
Are you using a template for your job?
Templates can include both job settings (the values you see in the PA job settings interface) and InDesign style configurations (the content which PA can export to the file current.txt -- which records style changes in InDesign).
The most likely cause of the warning is that your current job settings are being adjusted by some style settings from the template you are using which result in the kind of spacing values problem I described above.
Perhaps this explanation helps you to know where the problem may have arisen. If you're not sure, please open the job in PA and then use the Help > Report a Problem tool and someone from the PA team can help investigate the cause.