I've encountered these sorts of problems as well. Don't really understand why they're so difficult to fix.
I'll field this one...
They are difficult to fix because they just don't care.
I've had a few gripes in relation to Hearthfire, and we are now seeing glitch compounding on glitch, right back from the original game release, through Dawnguard and now Hearthfire, and there is still no serious information coming out from Beth, nor apparently, any serious attempt to rectify what seem to be a mass of problems.
It may appear harsh of me to say it, but Beth has never had a credible reputation when it comes to game stability or problem fixing, and that, I would suggest, is because they don't focus enough on the areas of troubleshooting or quality control. That is indicative of poor management, from the top down. This isn't an unsupported allegation, I could go back through hundreds of threads over a range of games and highlight problems dating back years that have never been resolved, never had an explanation provided for, etc etc.
I'll be fair, Beth makes good games...but they also produce cr*p programming in the same product. It's a crying shame they can't get their act together.