Old questions marked as duplicate of newer ones?
14629
Should I vote to close a duplicate question, even though it's much newer, and has more up to date answers?
135386
Should bug-report/feature-request *questions* that duplicate Grab-bag *answers* be closed as duplicates?
91152
Feed algorithm changed? Lots of duplicates
138119
Duplicate question close reason says "already has an answer," which is often false
100366
What is best way to find duplicate questions?
123327
Why do my "How to" questions often get renamed to "How do I"?
9026
"Possible duplicate" notice not removed after reopening question
104491
Single question thread with multiple questions, some duplicates
78555
Double booked - User bookmarking question recorded twice
55508
Should I copy my answer to a duplicate question to the original question?
20899
Linked and Related sections contain duplicate links to questions
60643
Should Stack Overflow/Exchange have a mechanism for marking obsolete questions?
135709
Duplicate post notice missing the duplicate
83666
What to do about deprecated questions & answers?
35162
Duplicate questions without answers
130608
Why can we flag/vote a question on Meta as duplicate of another question which has no accepted/upvoted answers?
13649
What to do with cross-site duplicates?