You are trying to initialize a new optimizer and initialize the scheduler to another last_epoch.
As the optimizer wasn’t used in the scheduler from the beginning, the param_group initial_lr is missing.
What is your exact use case?
Would you like to use the scheduler as if it was already used for 100 epochs?
If so you could set last_epoch=-1 in the instantiation and call the scheduler 100 times in a dummy for loop.