RE @Jamie Gerace's comment: I concur. What gives Atlassian team? If you're going to transfer the issue/ownership, you should transfer the votes & watchers too!!!
(Maybe Jira won't let the support team clone the voters & watchers? ... if that's true I believe it further underscores the need for Atlassian to fix this bug)

They didn't even link the two issues together.  This issue has been open for 7 years, the new one a few months.

So you moved it from this ticket with many more affected customers to a new ticket with few affected customers, sketch.

Dear All,
The current issue :
    When moving a Jira issue from one project to another - any completed Sprint that is in the Sprints field will be automatically deleted from the issue.
will be continued in this JAC ticket, please be informed that we are working on solving this issue 

As this ticket was originally related to another issue - the initial report been opened under new JAC :
https://jira.atlassian.com/browse/JSWSERVER-21518

Issue details:
    Bulk edit and of Sprint field and Bulk Move will remove issues from closed sprints
    When a sprint is closed but it still have open issues, then the issues go back to backlog (or a new sprint). If an user tries editing the sprint field on one of these issues, he has the option to add a new value but he can't remove the closed sprint. When the sprint field is edited through 'Bulk Operation', the closed sprint is removed from the field and so a new value is added instead of keeping both.

If you experience this issue - please watch it under new JAC ticket

For a particular sprint, one can see the old/new sprint values in the Sprint Report details. 

Assuming a set of issues has already been moved, how can the affected issues and the missing values be identified?  I am not aware of a JQL option that identifies issues where the Sprint value changed, and even if you know that a change has occurred, how do you know what the old value was without going to every issue and recording the old values?

this is an absolutely fundamental problem, especially for calculating velocity

Why was this reduced to medium priority? It's a bug that can ruin systems.

I raised this issue with our Jira Align TAM today in hopes he might nudge this bug along. 

The only thing I have encountered is that you can include the closed sprint in the bulk update to retain the information (e.g., <sprint_1_closed_ID>,<sprint_2_open_ID>). This is probably not a work around for all situations.

This is insane and needs to moved to the highest of priority. There is no documentation on this and it's literally ruining systems.

@Jamie Gerace this is absolutely ridiculous. We just faced the same problem when we bulk moved issues into a different project. Were you able to work around this issue on further bulk moves? Any idea how to retain the sprint information when closed issues in completed sprints are moved from one project to another?

As Jamie Gerace said, this is particularly problematic for our team when moving issues between project because there is no warning of any kind. We checked all the normal places, pressed Move, and now we have lost all our metrics!

It also happened when moving an individual issue, so it appears there is no way to move closed issues between projects without losing all that history.

This kind of bug should not exist anymore in such a mature product. It's been almost 5 years since this was logged and I don't get it why there is still no solution.

Absolutely astonishing that this bug was reported in 2016 and still no warning given in the UI about this during a bulk move operation. Absolutely devastating consequences per the comment above. We had no idea this was a bug and just completely corrupted our system essentially and will require hundreds+ hours to even attempt to remediate to an acceptable level. 

I am migrating 150k+ issues from one project to multiple others and all closed sprints have wiped out.

I have searched the community and google and there is NOTHING about closed sprints not carrying from one project to another in the same instance.

And another important thing to note...when I am bulk moving, there is NOTHING telling me that sprint field will be wiped. I've already migrated 50k issues from one project to multiple others and all historical sprint data is GONE, no warning, no documentation, nothing. I am FURIOUS. I have been so incredibly diligent to ensure data remains on issues in this migration and then this happens. 

If there is any documentation I'm missing please direct me to it, or at a minimum tell me that closed sprints won't carry over when issues are moved from one project to another if that's the expected behavior.

We have Jira installed locally and we faced the same problem. This is a major issue because at the end of the sprint not all issues must go back to the backlog, some should go to the next sprint, but in Jira you can only choose to move all not finished issues back to the backlog or to the next sprint. Therefore we moved all not finished issues back to the backlog and then we used a bulk update to move only some issues to the next sprint, but this operation deleted the previous completed sprint from them.

The only work-around that we can imagine is to use the scrum board to find all the issue and move them manually one after the other in the next sprint or configure a quick filter with all the issue keys to simplify the process. Anyway this is a bug, because also in the Atlassian documentation is written:

As we can't use bulk edit to overcome JSWSERVER-20206 which affects us heavily, we'd really love to see this fixed AND have the severity set higher than "Minor" - using bulk edit is recommended as the workaround for the referred issue... makes no real sense, doesn't it ?

I'd love to see this feature

I'd love to see this fixed, or an additional bulk edit option to remove specific sprints from tickets instead of replacing everything that is there.