Both Eldertides and Wildhorn WB daily quests bugged. Either don't get credit for killing bosses or can not pick up the associated items. Both have bugged at one time or another = pickup first then no boss credit. Kill boss(es) first then can not pick up items. If there was at least a pattern that worked consistently, then could adapt play to get around the bugs. But having to go through the entire WB kill only to discover it has to be dropped and picked up again is a major frustration. Sadly, with the WB's in new content not being able to be soloed, it is virtually impossible to do extensive testing of these quests prior to launch. In fact, the ESO quests seem to get more and more buggy with each new content. It seems as if new content takes a higher priority than fixing buggy quests -- especially at the WB daily quest level.
Reminds me of Windows 1.0 and frequently recurring BSOD. Telling users to just drop and restart quest is a lot like Mr. Gates saying - just reboot your computer.