Your output seems to be similar to mine, At the top the Diff is set to 19.7G this is the current difficulty, then each item in the list shows a different Diff such as 15/10 (I have no idea what this means), the difficulty changed to 1024 is I think a message showing that for some reason the difficulty of the work sent to you has been reset, this does not happen very often for me but it may be a sign that your internet connection is not responding quickly enough so the pool is sending you easier work so you can catch up (but this is just a guess).

Hopefully someone with more experience will confirm the reason for this.