Yup it did it on mine too. I have a feeling bilstein puts a little extra "oomph" in the shocks compared to factory. While the travel is the same, the shock itself has a bit more pressure loaded in which relieves a bit of compression on the spring and it causes the car to ride a touch higher.
If you were like me and were playing around with the bilsteins before installing, put some pressure on the shock to compress it and you find it has quite a bit of push back...put two down and push on each one and you can practically lift yourself up on them before they start to compress.
It's true struts are not meant to carry the weight of the car, but they have internal pressure which want to push the strut out and it takes pressure to compress it. Compare a worn out shock that has no pressure anymore and won't even push out unless you pull on the shaft to one that has enough force that you have to lift yourself off the ground to get it to compress, and you can see while that little bit of extra oomph is enough to make the car ride higher.