'Exclusion period' is to protect you from a loss-making scenario where you issue a refund let's say after 10 days BUT the customer has already redeemed their points.
Points are in 'hold' during the exclusion period and cannot be used to claim rewards. So for e.g. if you have setup exclusion period= 30 days and Jane buys products from you. Although, she will get the points BUT will be unable to redeem them for 30 days (the exclusion period).
Exclusion period setting can be found in the "Business Settings" tab.
