Master/Rogue Exile Spawn Frequency (Haku & Orra v.common)

(I want to preface this by saying that as a former software QA guy, I hate myself for posting such a vague bug report. Please forgive me.)

I'm playing a character (Witch/Necromancer named Lealynn if that helps) that I created early in the 3.0 beta period but without beta access (probably in 2.6.3). I played her through to the end of Act 4 Normal, then stopped playing until after the launch of 3.0.

I have noticed that I encounter Haku in the wild far more often than any other master. Unfortunately I didn't notice this until fairly late in the game, but looking back I'm very confident that over 80% of master encounters have been with Haku, and I'm reasonably certain that it's actually over 90%.

I've also noticed that when I encounter rogue exiles, I see Orra Greengate far more often than any other rogue exile--again somewhere in the 80-90% range.

I first noticed the master situation when it took me forever to get Catarina to level 2 to invite her to my hideout. I encounter her for the first time some time before the end of Act 4, but my second encounter with her didn't happen until after I had reached Act 7, and I think it might have been Act 8. This struck me as unusual, but not yet noteworthy--just bad luck, I figured.

Since then I have been paying more attention to when I see masters in the wild, and there is a clear bias towards Haku.

The situation with Orra Greengate is less clear. I run a zoomancer and do it is possible that I am more aware of Orra because I tend to see her Rain of Arrows even if my minions kill her quickly, but even so I never fail to notice when I have killed a rogue exile (thanks to the distinctive item drop pattern) and I am fairly confident she is over-represented.

If there is anything I can do to provide more information please let me know. I can start recording encounters with masters and rogue exiles if it would help.