Trouble with Variations - variation no longer exists

I have multiple listing of product in the Home Kitchen / Art and Crafts / Other Arts and Crafts section but am have issue with the variations. I used to be able to choose Size Name but now the only variation options is ‘Colour’

Does anyone know why Amazon does this? My product doesn’t ‘sit’ in any other category nor can I find one with ‘size’ … It seems a simple concept I want to sell a 1kg 2kg a 4kg pack and offer the customer the choice. What is really frustrating is I have multiple ‘old’ listings that did have this option.

Is there anywhere I can see which categories have which variations?