One of my forms seems to be disappearing from time to time, is there a certain reason as to why?

Could you please tell us from where it disappears? Do you have your form embedded somewhere? 

If you do, please share the link to the website.

We'll wait for your response.

Thank you!

It disappears from my 'shared with' folder. But it disappears and then
reappears out of the blue. It is embedded but the site is private
...

Thank you for additional information, that issue should be fixed. If you experience any further problems please let us know.

Thank you!