If you are sure that you have setup your affiliate link and postback URL correctly, then it may be a timing issue.
For example, if a conversion happens today, but the visitor who converted entered your funnel yesterday, then today's conversion will be shown at yesterday's date, not at today's.
This is the way all tracking applications work, and for a very good reason. The "when it happens" approach used by the affiliate networks is fine too, as they don't care about traffic - but affiliates *DO* care about traffic.
For affiliates, it is more important to know what times of day produce the most conversions/revenue/profit, than what times of day delayed conversions arbitrarily happen at.
The former helps to day-part and optimize, the latter can be random and unhelpful other than knowing the average time it takes someone from ad to conversion. And FunnelFlux can still show you this "time to conversion" information in the drilldown reports.