“Any writing problem is a reporting problem” is a journalism adage. If a reporter is having a problem writing a story, it’s probably because of inadequate reporting (not enough quotes, facts, etc.). “Often, a writing problem isn’t really a writing problem at all. It is a reporting problem” was cited in print in 2008. “Writers block is not a writing problem, it is a reporting problem” was cited in 2013.
   
 
Google Books
Editing for Today’s Newsroom:
A Guide for Success in a Changing Profession
By Carl Sessions Stepp
New York, NY: Routledge
2008
Pg. 117:
Often, a writing problem isn’t really a writing problem at all. It is a reporting problem. If the writer does not have sufficient quotes, details, and facts, then it is time to stop writing and do more reporting.
         
BusinessJournalism.org
Reuters finds loan processor’s problems more serious than CEO said
By Rosland Gammon on Dec 10, 2010
(...)
Today’s Tip:  “Often you’ll find that what you think is a writing problem actually is a reporting problem. By getting a missing bit of information to fill in a gap in the story, the writing problem goes away,” Scot says.
     
Active Scientist
A mind at work: expert advice on science writing
Posted on June 5th, 2013
Posted by Georgeann Sack
(...)
Robert Lee Hotz provided the answer in one sentence: “Writers block is not a writing problem, it is a reporting problem”.
 
Twitter
Ivan Oransky
‏@ivanoransky
”“Writer’s block is not a writing problem, it is a reporting problem”: @leHotz via @byGeorgeJohnson @ActiveScientist http://bit.ly/14ibQb3
2:03 PM - 10 Jun 2013
 
Twitter
Howard Stein
‏@STUDIODOON
“I believe in the old adage: Any writing problem is a reporting problem.” —@readmatter https://medium.com/the-most-powerful-drug/joshua-davis-if-i-dont-make-it-happen-ill-end-up-back-at-the-phone-company-60ad7174718d?source=tw-f6d33a86596e-1401679217061 …
10:20 PM - 1 Jun 2014