The average time it takes to find a bug, enter it into a bug tracking system, and then verify the fix is around 30 minutes.
The higher amount of bugs found equates linearly to the cost of product functionality verification per QA team member. As a team, it equates exponentially.
That is real time and money spent on a reactive and non-productive, non-quality impactful action to product quality.
If you feel that the development team is introducing an excessive amount of bugs into the QA environment that you test against, then be sure to bring that up in an Agile Retrospective, and provide ideas for process/quality improvement. The customer, and your company's CFO will appreciate your effort in reducing costs and promoting better product quality.