RuntimeError: Set changed size during iteration (Me no good at threading, during training)

So I get this every other time I train, and the learning will throw a fit(pun intended) and abandon training mid cycle/epoch.

Exception in thread Thread-15:

Traceback (most recent call last):
File “/home/paperspace/anaconda3/envs/fastai/lib/python3.6/threading.py”, line 916, in _bootstrap_inner
self.run()
File “/home/paperspace/anaconda3/envs/fastai/lib/python3.6/site-packages/tqdm/_monitor.py”, line 62, in run
for instance in self.tqdm_cls._instances:
File “/home/paperspace/anaconda3/envs/fastai/lib/python3.6/_weakrefset.py”, line 60, in iter
for itemref in self.data:
RuntimeError: Set changed size during iteration

This error is so succinct that It’s impossible to tell where it came from, other than tqdm+threading.

Saw other related posts, and googled, but to no avail.

Any proposals, ideas? Halp?

I’ve never seen that cause training to fail - it should continue just fine.