Twice now I have missed a quest because a quest from the day before was the exact same quest given to that character that day. I am seeing Nikolvara's Kennel and Coldperch Cavern dailies way too often. It's about like this (results taken from 8 quests a day):

Nikolvara's Kennel: 35%
Coldperch Cavern: 35%
Argent Mines: 20%
Thukhozod's Sanctum: 9%
Zthenganaz: 1%
Watcher's Hold: 0% (only my main ever gets this one because he is the only one that has completed it which is a requirement for the quest to appear, but hasn't gotten it lately at all)

These are relative figures expressing how often or not often I get the quest for those Delves but seriously something is screwy with RNG lately, and it's kind of proven by how Maw of the Infernal, according to others, has appeared in Cyrodiil multiple weeks in a row when there are 9 other monster sets out there.