question: Trainer.fit validating before finishing current training epoch
context: When the train.fit() starts to train my model, it starts validating at 95% of training of current epoch instead of waiting until 100%.
  Why does it happen? It makes Val-loss/acc/miou not accurate anymore…
answer: the master progress bar that shows you the progress of the corresponding epoch consists of both train and val steps. So it completes the training within the first 95% of the total steps and the last 5% is completed for validation.