E-mail delivery delays or broken system?


I just checked my junk mail folder and saw that today and yesterday I received e-mails from people who sent them as early as May 4 and earlier.

I noticed a few weeks ago that my junk mail folder was steadily getting smaller, which I was pleasantly surprised to see and relieved that something was working. Then, in the past two days after seeing it go down to about 104 e-mails, I saw it jump in in 2 days to 150! So I checked and saw all these old e-mails that were finally delivered (about 6 or 7 legit) that were caught by the spam filter. They should have been received weeks ago and now I’m finally seeing them! What does this mean and why did it happen? Anyone else experience the same?