[NLP] punctuation_capitalization resume training fails
**Describe the bug**

When training PC from scratch, using the example configs, everything works fine, however if I try to resume an interrupted training from the last checkpoint, I get the following log entry
```
[NeMo W 2022-07-07 21:18:38 nemo_logging:349] /opt/conda/lib/python3.8/site-packages/pytorch_lightning/callbacks/model_checkpoint.py:378: UserWarning: `ModelCheckpoint(monitor='val_loss')` could not find the monitored key in the returned metrics: ['epoch', 'step']. HINT: Did you call `log('val_loss', value)` in the `LightningModule`?
      warning_cache.warn(m)
```
and all new checkpoints get a `val_loss=0.0000`

**Environment details**

- pytorch:22.04-py3
- nemo:1.8.2 installed with ./reinstall.sh, without numba install
