Now yesterday I was checking the instances again and of course one of ours was affected like usual. But what I also saw: A second lightsail instance was affected too and what was crazy is, that this instance is empty. Its a newly created ubuntu instance that did not have any running code (only a few files of a not running application in the ubuntu folder). How on earth would the 100% problem appear on a basically empty lightsail instance that has no user application running?
