Well.... this is weird.... I have found that quests are resetting. I thought I was losing my mind.

I played through with one character, so I am familiar with the quests when they appear. The first weird one I got was J'Zargo's Flame cloak quest. I picked them up, and later on, when I decided to try them, i didn't have the scrolls anymore. I though I might have stored them... but quest items usually can't be dropped etc. Hmmm....

Then, I got the Red Eagle quest.... did it. A while later.... picked it up again..... the place did not had the boss again though.... The J'Zargo Scrolls I was able to get from him again.... I wonder how many quests will be respawning! And how many will be "stuck" as a result of completing them once!

I tried to keep information to a minimum to avoid spoiler spanking! But this is really general discussion topic I feel.

On my last character I did the Red Eagle quest, I got it without ever reading the book about him. Finished the quest no problem. Many hours of gameplay later I made the mistake of picking up a copy of the book and I was given the quest again. Sadly there seem to be many, many copies of that book scattered around Skyrim... I just have to remember not to pick one up if I've already completed the quest once.

Red Eagle quest restarts every time you read that book. It's very annoying. This is a famous bug, and popular workaround is to be careful about not picking up the book.

Alternatively if you are playing on a PC, you can just get the Unofficial Skyrim Patch, by Kivan here http://www.gamesas.com/topic/1366865-wiprelz-unofficial-skyrim-patch-thread-6/page__p__20631705#entry20631705 which fixes that bug and countless others.

I just started using that with this character, pretty sure I didn't have it with the last one. So maybe that's one less glitch I have to worry about.

Sold. Thank you.