Yes, that sounds normal.
The way the system works is that all of the mechanics that move the slide are attached to the bottom of it.
Because of the weight of the slide, when the ram tries to push the slide out, the first thing that will happen is the bottom gets pushed out followed by the top.
There is also a nylon glide block under the slide. The slid will pivot on it as it goes in and out.
Hope that made sense.
Peace
Dave