What is MatchesEvent And MatchesRewards Means in Personalizer?

Question

My company tried to use personalizer to ordering recommendation list of item based on user context.

We have implemented it, but there's problem about the evaluation page.

in this image, we success to give Reward to our personalizer model.

But in Matched Events and Matches Rewards. I still don't understand how it works.
I tried to isolate environment of Personalizer, and Calling Rank API then Reward API with value 1 in local. but the matches event still 0. but sometimes they get increased.

My question is, what's condition to be fulfilled for Matched Events and Matches Reward? I can't find it in any documentation. And we need the detail about it.