Damn WLP001

I took part of an older yeast cake of WLP001 to make a starter with to brew a 70/-,and this has to be the slowest to flocculate yeast I have ever seen. Over 24 hours to flocculate out in a 35*F fridge, WTF ???  All I can assume is that I took the last jar of yeast I collected from the conical and it is the slower yeast to flocculate >:(