Builds taking twice as long since upgrading to unity 2017.3

Unity Engine
1

We have a rolling build system, it simply builds our project from the command line at every check-in.
We were running 2017.2.1 and out build time was about 1 hour, after updating to 2017.3 the build time is about 2 hours. Is there any reason this could be occurring?

2

I was hopeful when the last patch said this was resolved but it didn’t effect the time at all. The logs don’t show much.

*** Completed ‘Build.Player.WindowsStandaloneSupport’ in 7476 seconds (7475839 ms)