And a few weeks ago, it was another signature. And two month ago, a third. I guess it is an error in a repository, Cydia decides that something is not right and ignores the affected files, just to be safe. After a while, somebody with the ability to fix it does so. Until then, annoying but probably harmless.
This is just a error when the http request failed, usually due to server down or just a lot of traffic (like the first couple of weeks when a new tool is released), nothing to worry about