I want to welcome you to the forum. I don't know the answer to your question but hopefully someone here will.
Now that I told you honestly that I don't know I will say that I've been told what causes that kind of flaking is when the paint in the lower levels dries slower than the paint in the top level of the painting. It's a rule of thumb called 'fat over lean'. The leaner oil paint dries faster and the oilier or fattier paint dries slower so if you paint faster drying paint over slower drying paint eventually it cracks. Bottom line is there isn't much of anything that can be done about it. But remember this is only what I have been told by people on the internet. I have no first hand experience.
Now that I told you honestly that I don't know I will say that I've been told what causes that kind of flaking is when the paint in the lower levels dries slower than the paint in the top level of the painting. It's a rule of thumb called 'fat over lean'. The leaner oil paint dries faster and the oilier or fattier paint dries slower so if you paint faster drying paint over slower drying paint eventually it cracks. Bottom line is there isn't much of anything that can be done about it. But remember this is only what I have been told by people on the internet. I have no first hand experience.
