ok, got it!
I’ve read your colab and two things:

I think your train/validation split is a little bit weird. (That doesn’t affect the issue you are mentioning)
given that you want to convert to TFLite and it looks like it’s a simple image classification model, I’d suggest you try using Model Maker 2. It will take care of converting the model and doing all the magic for you. It will also make it easier to use it with the Task Lib 1


If you decide to use Model Maker, you can use a MobileNetV3 model spec (the model is available on TF Hub).
sorry for the non-answer