text: Title: About the problem of falling mAP when learning YOLOV8
  Body: ### Search before asking
  
  - [x] I have searched the Ultralytics YOLO [issues](https://github.com/ultralytics/ultralytics/issues) and [discussions](https://github.com/orgs/ultralytics/discussions) and found no similar questions.
  
  
  ### Question
  
  With the help of answering previous questions, I finished the YOLOV8X.pt version of the study with batch=8 with imgsz=1920. Looking at the learning outcomes, the mAP index started at 80 and went up to 87.2 and then finally dropped to 56. Should I think the training was not good in this case?
  
  ### Additional
  
  _No response_