Thumbs at Assets Export Panel doesn't update while replacing new images

Looking soltuion on facing issue:

Situation: 

I made a template to repeat few banners and from those sub layers, I have generated assets at Assets export panel. Now while making new banner images from the template, I relinked images but the thumbs at Assets Export panel doesn't updated according to new images and I unabel to export them with updated images.

do I need to find any script to export sublayers?