Page Content Gets replaced by “N;” for a page every few days

On my wordpress site i have page built with Visual Composer plugin, but from last few days the page’s content automatically gets deleted and replaced by “N;”

I don’t think its a hack, it just seems to be happening only with this one page.

This page is little complex as it uses, lots of Charts and tables and javascript and filters, so i’m unable to find the reason behind the issue, I hope someone can help me pointing to right direction.

Post content in database