Not sure what you are getting at. Even 16bit color space isn't unlimited and depending on how discrete values overlap/ coincide quantization can occur. Only working in 32bit can further expand that range. That aside it's really not clear how you work and what adjustments you apply. You would have to provide screenshots. Furthermore the histogram may not necessarily be an exact representation since it's calculated on the fly. Plus of course we really don't know anything about your RAW settings, color management, hardware acceleration settings and so on. This is really much more complex than just saying that the histogram looks crooked.
Mylenium