NEED HELP:Making Sourdough with cultured butter

Sourdough made with cultured butter

Sourdough made with olive oil

Hi all,

I never have luck with making sourdough successfully with cultured butter, not even once. No rise during bulk fermentation and final proof. Tried to wait for the dough to rise and drag for hours, the bread turned out super vinegary. Have no problem when using olive oil, the rest of the recipe being the same.

Is there a probability that the bacteria in the cultured butter is messing with my sourdough starter? Like maybe the former win over the latter and affect the whole "ecosystem" of my starter?

Since day one I've been feeding my starter with flour and water only. Is it that I have to feed it with milk and flour when building the levain as a transition period so that when it is used to make bread it will not be "lactose-intolerance"? 

Would be really grateful if someone would come along and shed some light. 

Recipe:

Bread Flour 100%
Milk + whole egg 60%
Sugar 7%
Salt 2%
Olive oil/cultured butter 3~3.5%