Hello all, I thank you in advance just by reading this.
I performed a migration from Jira server to Jira Cloud and used both the backup zip and the data zip.
The projects, issues and what not imported flawlessly but the users of the issues appear in this UUID form.
I have no problem changing the users by hand but every time I try to change a user, I get the error displayed in the second image.
It seems that if I create new issues the problem does not happen. The problem seems to happen only in migrated issues.
Any help would be appreciated, thanks again in advance, and best regards to you all.

