Why does Shopify show wrong product variant image?

Let’s say I have a particular product called Palm Shorts, and it comes in two colors (variants), blue and aqua. I currently have the aqua variant as the featured image. However, I notice that if the quantity of the aqua variant (which is the first variant listed) is at 0 (and the blue variant is available…let’s say the quantity is 5), then when the user chooses the product to look at, Shopify automatically shows the color name of blue (I assume because it is not available in aqua), BUT the image is the featured image (aqua). I feel this can be very confusing to the customer. Is there a way this can be fixed?

I would like to add that I am using the Galleria theme.

Another issue is that when a particular variant is not available, if that variant is chosen in the drop-down menu, the corresponding image does not show. The image stays on the last available variant image.