It's an issue on YouTube's side - they're having issues with the feeds again. All of his latest videos are still "sending to subscriber feeds". Not much you can do about it other than waiting for Google to fix it sadly.
In the meantime you can either check his channel directly or the forums for new video threads, we're pretty much uptodate.

I usually just check on the youtube channels so I would care less of the problem.

Its called a subscriber burn.Because you didn't what some anymore YouTube thought that you were no longer interested to Pewdiepies videos and filtered them out of your sub box.But I am not sure