trains only on first task when different trainsets are passed each time

I am implementing a model for continual training. Hence, I train my model on different tasks and test them on previous tasks. In lightning versions 1.3x, fits the models to only first set despite passing different trainset each time. When I check the accuracy on different tasks, it is maximum only on first task. When I shift to version 1.2.10, it trains expectedly on each trainset.