Skyrim has a lot of silly bugs like this. Another reason that makes me believe the game was rushed without proper QA.
One of my favorite quest bugs happened when I entered a random fort. I fought my way through the fort and when I arrived at the courtyard there was a lever that opened the main gate to the fort. I activated it and left the fort through the main gate. Afterwards I found a camp outside the fort with three guys hanging around. One of them told me that his fort was taken over by bandits and he asked me to help him. Yes, sure, I said. So he told me to open the gate of the fort by activating a lever in the courtyard. Well, obviously I just opened the gate with said lever. But dialogue options? Nope. So I had to tell him that I would do the job (a job I had already done, but whatever). Then I had to walk through the whole fort again (directly going to the lever didn't work as that was not my current quest objective). When I arrived at the lever I activated it and closed the main gate. Funnily enough the three guys magically appeared inside the fort even though the main gate was closed now and thanked me for liberating the fort for them. :facepalm:
Indeed. The three glitches that I mentioned in the OP were of the major variety though this kind of glitch that just makes you do something inefficiently or hinders you are super irritating though not game-breaking, or erm...excuse me "quest breaking," lol. I have found dozens of these. Most recently I couldn't rename my weapons so instead of walking around with badass swords named Siphon and Leech I have Daedric Sword (Legendary) and Daedric Sword (Legendary). Waiting in front of shops for them to open also causes an irritating glitch where they are still locked after the waiting period is over. I have had situations where I saw something a merchant had that I really wanted but couldn't aford but by the time I walked across town to sell off some of my inventory their entire inventory had changed. Not just the single item which might make sense from a roleplaying perspective. I.E. someone else beat me to it, but the entire inventory, every single item had been turned over in a matter of minutes. You can also exploit the game by saving, killing a merchant and reloading your last save to reset their inventory, though I have not tried.
All of the above are just examples of sloppy rushed design to get this game on the shelves by Christmas. It is like they are saying to their fans "We know you are stupid enough to keep playing this trash no matter how many bugs there are so why try to release a good final product the first time. We'll fix it when we're good and ready." The counter-example that I usually reference is Blizzard's approach to quality. Can you concieve of a Blizzard game being released with such glaring bugs? Hardly. Even World of Warcraft (which is infinitely more cumbersome that TES since it requires constant updating) is less buggy than this piece of crap and they have to actually maintain it in the cloud. Diablo III will be perfect when it is released because it has been in development since before a generous portion of it's target audience was born. Get it right the first time Bethesda or don't do it at all.