Additional variation images not displaying when variation is selected

I noticed recently that when I select a particular product variation using the color swatches and size select dropdown controlled by this plugin, the additional variation images are not displaying unless they happen to also be used in the main product gallery. If the same images are defined in the main product gallery as I have defined in the additional images for that variation, then they will appear, but if I do not have them defined in the main product gallery, then they do not appear when I have that variation selected on the product page even if I have defined additional product images. This used to work correctly several months ago and I do not know why it no longer works. For products with lots of variations, I would have to have a really huge main product gallery in order to get variation galleries to appear and I do not want to do this.

The plugin also used to switch to color variation images when only the color attribute was selected but that no longer works either. Thanks for your help!