I moved a task from board to board and it is gone.How did that happend?

[Anna Rogowska]

I was moving a task from board to board twice in the same day. What we found out is that it was merged into a completely different task and the original is gone. 

How to report that kind of a bug directly to Jira devs?

[Sudarshan]

Hi,
I understand i am late in answering this question, but still incase you still need it.

you can ask the https://support.atlassian.com/contact/#/  for such questions.

Before that check with your organisation Jira Admin and then move to Atlassian Support.