Hey everyone, I’m trying to build a region proposal network with small a convolutional head and vgg16 as a backbone for feature extraction. I’m having an issue where the parameters are not being updated (currently fine tuning but will freeze the extractor later), and when I check gradients all of them are None. I keep getting dummy predictions and the loss isn’t decreasing. I’ve pretty much scoured this site, the docs, and google for answers, but I’m not sure. And debugs I might have missed? Thanks