I’ve been using flake white from Utrecht a lot. Lately, I’ve run into the same problem, namely, tubes with excessive oil content. When I open a fresh tube, a lake of oil pours out. That is what happened with the last tube I opened.
You can see what I mean in this photo. I placed the palette upright to take a photo. When I later retrieved it, I discovered the white had flowed down the palette’s length. That also happened with a light gray I mixed. None of the other colors slumped this badly.
Excessive oil renders the paint useless for my purposes. It robs the paint of body, as you can see.
I’m kicking myself because I broke my rule that limits buying one tube at a time. I have 2 new Utrecht flake whites in my drawer. The last time I broke my rule I was also burned. Both tubes of Winsor & Newton flake white were partially dried. The tubes had chunks of dried paint throughout–useless. Soon afterward, W&N stopped making the all-important flake white.