Understanding the Progress Bar
I train on MNIST with data loaders defined below (full train / test sets with batch_size=128).
'val_check_interval': 0.1, so per training epoch, I have 10 validation runs.
Now:

10000 (test) images / 128 (batch_size) = 78.125, so steps such as 54/79 do make sense.
60000 (train) images / 128 (batch_size) = 468.75, so I'd expect something like 120/469.

What is the "1259" representing in the progress bar? I can observe in tensorboard, that the epoch number goes up at exactly 459.
Validating:  68%|██████▊   | 54/79 [00:08<00:03,  6.57it/s]
Epoch 4:  78%|███████▊  | 976/1259 [04:01<01:09,  4.05it/s, loss=19279.273, v_num=0]

Code
Data Loaders
    def train_dataloader(self) -> DataLoader:
        """Pytorch-lightning function."""
        transform = torchvision.transforms.Compose([torchvision.transforms.Resize((32, 32)),
                                                    torchvision.transforms.ToTensor()])
        train_set = torchvision.datasets.MNIST(root=DATA_DIR_PATH / 'mnist_data',
                                               train=True,
                                               download=True,
                                               transform=transform)
        return DataLoader(train_set,
                          batch_size=128,
                          shuffle=True,
                          num_workers=0)

    def val_dataloader(self) -> DataLoader:
        """Pytorch-lightning function."""
        transform = torchvision.transforms.Compose([torchvision.transforms.Resize((32, 32)),
                                                    torchvision.transforms.ToTensor()])
        val_set = torchvision.datasets.MNIST(root=DATA_DIR_PATH / 'mnist_data',
                                             train=False,
                                             download=True,
                                             transform=transform)
        return DataLoader(val_set,
                          batch_size=128,
                          shuffle=False,
                          num_workers=0)
What's your environment?

OS: Ubuntu 20.04
Packaging: pipenv
Lightning Version: 0.8.5