I get the exact same thing (in developer tools upon variable inspection).  So, the problem is not catchable in dev tools in the browser.
But, if you run a for loop and try to use that data, you will get a stale version of it, unless I’m doing something wrong. For example, how would you extract the strings from that columns array at the end of the columsdragged event?  I have done this several times and I always get stale and outdated state of the strings in their original order.  I gather that you will get the same result if you run the code I printed in the second post. Please advise.