Add executions to folder returns 500 or 404 status code

[Volodymyr Shmigel]

I have some strange responses when adding executions to folder(https://zfjcloud.docs.apiary.io/#reference/execution/update-executions-in-bulk/update-executions-in-bulk). Here is one example when i separeted three requests by red line. So the first one is fine, it returns correct response. But the second one is the same in terms of url, projectId and versionId but with different issues and it returns 500 status with an empty body. The third request is retry of second request with same  parameters, but it returns different status and body. 
I create new jwt for each request. This exception happens when running and publishing our tests. I think it doesn't relate to particular test, also rerunning these tests againg can upload executions without any exceptions