I don't think this happened before the update.

On action bar buttons that are assigned with macros performing multiple actions you can no longer benefit from pressing early.

E.g.
/macricon "Fast Blade"
/ac "Fight or Flight" <me>
/ac "Fast Blade" <t>

While the GCD is on its way to reset you could activate the action half a second before and the skill would fire off once GCD passed. Now you need to wait a fraction of a second until the GCD has reset. This happens regardless if the OGCD is up.

If the skill is a directly placed action then it works as pre-update.

Was it always this way? I have been quite button mashy since I added these macros so possibly never noticed.