It’s not the final solution but it’s the hack that got me productive again in the meantime. Note that this graph functionality isn’t something I added and I haven’t had the time to investigate/fix it and won’t for a while. I originally omitted the graph functionality when I created the tensorboard callback because it was causing too many perplexing problems back then and the benefits were minimal in my opinion.
I think you’ll have to try for yourself and dig from here. I’m as out of the loop as you are as I haven’t been involved in any fastai2 development and am still on fastai1 myself.