Just speculation, but Clark and Dorsey may have been having troubles for quite some time. Maybe Clark (and the Hunt family) were thinking that they may have to get rid of Dorsey before long, and because of the conflicts didn't want a Dorsey friend (Chris Ballard) as the heir-apparent to the GM position.
Knowing Chris Ballard was seen as an up and coming GM candidate, the Hunts may well have let him go to clear the decks for getting rid of Dorsey. Now, once Dorsey leaves, the heir-apparent is Brett Veach, who is not a Dorsey person. We know Veach is a Reid person (see below). Additionally, Reid is explicitly kept out of the GM interview process, which is run by Clark and possibly Donovan.
Chris Ballard was a friend of Dorsey's before coming to KC:
http://www.chiefs.com/news/article-2...7-6294a893f69a
Brett Veach was hired by Andy Reid in 2004 as an intern with the Eagles.
http://www.si.com/nfl/2017/07/10/chi...ch-john-dorsey
As an aside, Mike Borgonzi was with the Chiefs since 2010, so he pre-dates both Reid and Dorsey here in KC and doesn't seem to have any prior connections to either one.
Again, this is just speculation, but it could explain the facts we are seeing.