When trying to move an issue to another project, we receive a 500 error page, ive gone thru the audit logs to see whats changed, the only changes that correlate with when the issue started is that of a screen change, ie, on a screen, a tab was removed, a new tab was added, since then ive re-added the tab that was removed and added the fields that were configured for that tab.
ive done a few lock re-indexes.