I do not use vanes, therefore I do not know anything about the different brands and the material composition used in each.

However, from what you describe, it is possible that the Duravane does not have a rubber resin in its composition, and the Flexfletch may. Solvents such as acetone, tuolene, xylene, etc, regardless of what the Flexfletch manufacturer suggests to use as a cleaner, can soften rubber, degrade some resins used to make rubber pliable, and can dissolve rubber-based adhesives used to secure the vane to the shaft. Even the strong fumes can have a degrading affect.

I do not know if the acetone is at fault, but it is a possibility I would not dismiss considering your problem occurred after using acetone. Maybe you should contact the Flexfletch company and inquire.