What are some challenges you face while managing QA teams in an Agile setup?

Many organizations separate “developer” and “tester” roles, making it difficult for the whole team to take collective responsibility, QA team should be included in sprint planning, KT sessions provided by the product team to understand the scope and requirement for upcoming functionalities. A major challenge faced  is when developer finishes a user story right at the end of the sprint, leaving insufficient time for testing. This results in a bottleneck and often leads to incomplete work being spilled over to the next sprint, thus QA team maintain the quality throughout the testing activities.