Thanks for contacting us again for your concerns.

We apologize for any inconvenience potentially caused by this work.

You do not need to change your robots.txt.

As the information provided by our crawl engineers, this is for the soft 404 scrub that we are doing on hosts now.

It is under our control.

We know that the works leave the strange path as

/kjhgdkjhf1goifj2lktjelj34knfhjguih8bbj

[… Regards, AltaVista Crawl Support]