PricklyRaven28 basically this is the issue:

python -m fastai.launch <script>

There are multiple copies of the script running, but they are Not aware of one another.
are you getting any reporting from the diff GPUs? I'm assuming there is a hidden OS environment that signals the "master" node, so all processes can communicate with it. This is what we should automatically capture. There is a workaround the fastai.launch, that is probably similar to this one: