Fleiss Kappa observed and expected agreement



Can someone help me understand the difference between Observed Agreement versus Expected Agreement?

I ran an IRR through ReCal3.0.
The data consisted of 15 raters of 30 different cases. The raters made a Approve or Deny decision on each case.

I received the following:
Fleiss Kappa - 0.826
Observed Agreement - 0.935
Expected Agreement - 0.628

On a different set of decisions. Same number of raters and same number of cases, I calculated an IRR through ReCal3.0 and received the following:

Fleiss Kappa - 0.93
Observed Agreement - 0.965
Expected Agreement - 0.504

Is there any interpretation that I can make from the different Expected Agreement scores?