I just counter a strange problem recently.
I have a very normal ConvNet and doing some image restoration tasks.
The overall training is fine, my model can yield good results, but the behavior of the first epoch is kinda strange and I just need to confirm if there is something wrong:

the loss at the end of first epoch is like 6,000,000+, but instantly decrease to less than 10 on second epoch and then everything seems normal…after 100 epochs the loss is around 5.

Any explaination for this phenomenon, or does anyone counter this before?
Thanks in advance.