It looks like there is a potential deadlock when two Content Items are edited at the same time and published.

It happened on Travis, where two scenarios were running in parallel:

https://github.com/ezsystems/ezplatform-admin-ui/blob/1.5/features/standard/ContentTypeFields.feature#L78

https://github.com/ezsystems/ezplatform-form-builder/blob/1.2/features/FormBuilderTests.feature#L131

Both of them are editing an existing Content Item and publishing the new Version.

In the attachment there is a screenshot of the exception that happned, also the following error was displayed in browser's console logs:

│  http://web/admin/content/edit/draft/85/2/eng-GB/86 - Failed to load resource: the server responded with a status of 500 (Internal Server Error)