You played "Golden" through and the chords held. The time didn't. You rush the quarter-note sections, and until this lesson you couldn't hear yourself doing it. Now you can, and you have a system that trains it out. "Blinding Lights" waited on purpose.
The full play-through at the top of the lesson settled it: harmony is not the problem anymore. The problem is a specific one. When the track's groove kicks in — each beat splitting into threes, da-ka-da, da-ka-da — you speed up.
You downloaded Pro Metronome in the lesson. The setup: 4/4, subdivision set to triplets (the fourth option), beat one on the top accent rung, beats two through four on the middle rung. That gives you the song's da-ka-da feel instead of a bare click.
On stage you'll be at your worst — people, pressure, dinner, a racing mind. So practice under ambush conditions. Runners train with a weighted backpack; a stuffy room and a strange upright are your backpack.