We created a program and it modified the strat and end date of issues it could find. This update was unintentional. We don't use the Start and End date for 95% of the issues that got modified in the process. The program was deleted. However, the start and end date modification still exists. Our default JIRA screen scheme for 95% of issues doesnt show these two dates and we don't use them. Initially, we believe that these dates are BigPicture fields and not JIRA fields.
In any case, is there a way to undo this update across all the issues (4k+). Note that I am project admin of only of the 6 projects that these issues belong to.