Where is the cursor located when you started? With Mini-Find, the R button will replace the current match, and move to next occurrence. From the first screenshot, I see all the matches in the selection highlighted, but I don't see a highlight for the current match. If there isn't a current match to replace, then it searches for the next occurrence. From the screenshots and what you are describing, I believe it is working as designed.
UPDATE:
Okay, I think I did just find something odd with wrapping in a selection in testing. Are you seeing any messages on the status line about wrapping or search past the starting point?