An errant merge gone wrong could lead to this? (13)
I believe the answer is:
rearrangement
'lead to this?' is the definition.
The definition suggests a singular noun which matches the answer.
'an errant merge gone wrong' is the wordplay.
'gone wrong' indicates an anagram.
'an'+'errant'+'merge'='anerrantmerge'
'anerrantmerge' anagrammed gives 'REARRANGEMENT'.
'could' acts as a link.
(Other definitions for rearrangement that I've seen before include "New layout" , "Moving around of component parts" , "Act of changing layout of items" , "A new ordering" , "Act of moving things around" .)