Color override is no longer possible on icon instances at all.

I am managing a 1000+ icon library. Each icon is a component with variants for different sizes and regular/fill theme (+bespoke properties for icons that need it). All icons are flattened single shape, fill-rule corrected and all have a single layer named “Shape”. (Everything is set-up exactly like MS Fluent system). This library is published to multiple design files where colors are being overriden depending on states etc. inside their parent components. All of this worked before summer vacation, coming back to work now almost all icon instances have reverted back to the default color variable and I am completely unable to even re-override them with the correct colors again. The color is not editable at all now. Why are the overrides broken?? Why can overrides no longer be applied at all?? This is breaking an entire design system at a very crucial point in time for us, any help is very, very much appreciated. Thanks.