How to benefit Data augmentation when it yields to different classes
You could rotate images manually (without using ImageDataGenerator) and save it to disk.
That way you would know which images you have rotated - so you would know which images have changed the class.

After it, when using ImageDataGenerator, you need to set rotation_range to small value in order to be sure that it won't change the classes of images.

Examples how to rotate image manually can be found here: https://stackoverflow.com/a/43864937/5997950