Solved by Alexey_Demyanchuk in post #10 
              
              
                True. You should detach it only once and only after collecting the features using the Resnet. Then, you can train as usual. The code snippet in my previous post is the preferred way to do so (in my opinion), as it is more explicit: you don’t need to train Resnet - set it to eval, you don’t want pyto…