If I recall correctly (and @ddollar can probably verify) this was implemented but later removed because CodeBuild didn’t keep things (was it Docker layers?) cached in between builds which made it all slower in the end.
But it was a long time ago, maybe CodeBuild has gotten smarter since then?
@robert now AWS codebuild supports local caching so the docker layers would be cached for the current build and the intermittent builds could you please try picking this up again that would be helpful.