The loss you were at isn’t saved so you can’t trust what it tells you when training resumes. First it’s not an average of all the losses since the beginning of the training, just since you restarted. Then the first time it’s logged, it’s divided by the wrong number (a number way too big) which is why you have that low loss.
I’ll look at this tomorrow and see if we can have the same losses printed in a full training and a resumed training.