This issue persist in ckeditor, which sometimes manipulate html tags or ckeditor adds additional codes like <p> or <span> or remove some style code, so to avoid this issue please carefully edit your page html data outside (first switch ckeditor in source mode then copy html data in text editor like notepad++ or sublime text and then edit and after edit paste html data in ckeditor) ckeditor and then save it. If you want we will disable ckeditor in your Front CMS module to avoid this issue then please contact to customer support. In upcoming version of Smart School we will try to replace ckeditor to tinymce editor and will provide another option in settings to disable/enable rich text editor from Front CMS.