When does UI image refresh after changing a material property?

I have a bunch of buttons for items, but you can also set the colour of those items. So I want to show the current colour on these item buttons.

So I gave these buttons' images a material, and changing colour changes the colour of that material. ( with .SetColor() )

I find you don't see the change right away, the colour on the item buttons stays the same.

It will update if you disable and re-enable the parent of the buttons. I tried LayoutRebuilder.MarkLayoutForRebuild but that doesn't seem to include the Image materials.

When does the Image refresh after changing a material property? And how can I force that to refresh when I want?

 

I tried a few things but for now I'm doing the disable / re-enable.