Conflict between precision and plugins arguments in Trainer
@adamlin120 thanks for reporting the issue.

Can you please try https://github.com/NVIDIA/NeMo/compare/main...akoumparouli/update_megatron_gpt_cont_training and let me know if that fixes the issue for you? thanks. This issue is stale because it has been open for 30 days with no activity. Remove stale label or comment or this will be closed in 7 days. This issue was closed because it has been inactive for 7 days since being marked as stale.
**Describe the bug**

When attempting to train a model using Nemo 2403, a `ValueError` is raised indicating a conflict between the `precision` argument and the `plugins` argument being passed to the Trainer. The error message states that both `precision=bf16-mixed` and `plugins=PipelineMixedPrecisionPlugin` were received and cannot be used together.

```python
Traceback (most recent call last):
  File "/opt/NeMo/examples/nlp/language_modeling/megatron_gpt_continue_training.py", line 167, in main
    trainer = Trainer(plugins=plugins, strategy=strategy, **cfg.trainer, callbacks=callbacks)
  File "/usr/local/lib/python3.10/dist-packages/pytorch_lightning/utilities/argparse.py", line 70, in insert_env_defaults
    return fn(self, **kwargs)
  File "/usr/local/lib/python3.10/dist-packages/pytorch_lightning/trainer/trainer.py", line 401, in __init__
    self._accelerator_connector = _AcceleratorConnector(
  File "/usr/local/lib/python3.10/dist-packages/pytorch_lightning/trainer/connectors/accelerator_connector.py", line 134, in __init__
    self._check_config_and_set_final_flags(
  File "/usr/local/lib/python3.10/dist-packages/pytorch_lightning/trainer/connectors/accelerator_connector.py", line 271, in _check_config_and_set_final_flags
    raise ValueError(
ValueError: Received both `precision=bf16-mixed` and `plugins=<nemo.collections.nlp.parts.nlp_overrides.PipelineMixedPrecisionPlugin object at 0x1551053e0d90>`. Choose one.
```

**Steps/Code to reproduce bug**

1. megatron_gpt_continue_training mixtral 8x22b with Nemo 2403 image.

**Expected behavior**

- This issue seems to be related to [Issue #8848](https://github.com/NVIDIA/NeMo/issues/8848), where a similar error was encountered when converting Mistral/Mixtral models to the Nemo format.
- [PR #8908](https://github.com/NVIDIA/NeMo/pull/8908) partially addressed this issue by removing precision args in the trainer due to a PyTorch Lightning (PTL) update. However, the changes were not applied to the training script.