Hi Rui Wang,
I have checked the activities and found its logging other activities other than the particular form submission.
In \CMS\App_Data\CMSModules\WebAnalytics folder i didn't find any file.
I have checked all the setting related to online-marketing and contact management all are enabled.
Recently I have submitted the form but its not added in the contact group. I have checked the contact activities its not logged any thing related to this form submission while its showing the activities for other forms.
I am not getting why its not logging any activity for this particular form.