This is one of those things that catches freelancers off guard, especially the first time it happens. The client is friendly, engaged, and full of praise while the work is going on. Then the invoice lands in their inbox and suddenly they are hard to reach, slow to reply, or full of new concerns about the work. It is hard to know whether it is a cash flow problem on their end or something else. Either way, it puts the freelancer in an uncomfortable position. What do you think is usually behind that sudden change in attitude when payment comes up?