This appears to be the norm. It also will not change to V4 until the engine is up to a certain temp too. I can tell you that I found a sweet spot yesterday where it stayed in V4 for awhile when I was neither braking or coasting. I was on a flat stretch with just enough pressure on the throttle to hold it around 55 mph. It stayed in V4 for a couple of miles doing this.
2017 GMC Canyon All Terrain X Quick Silver Metallic