This may be a compatibility issue. We would like to make sure this bug exists in a minimal setup or not. Do you have a staging site(clone copy of the live site)?
Please let us know the exact steps to reproduce the bug on your site.
Thank you for the updates. Please note that we are not able to reproduce the issue exactly in our test installations. Therefore please let us know the exact steps to reproduce the bug on your site.
Also, please fill in the private details fields after a full site backup{mandatory}. I would like to access the admin area of your site for further checking. Refer to the following links for more details about our private information-sharing policies.