ACX Crystal AIS track (YouTube)
From the video it looks like the Crystal had initially changed course to the SE, possibly to give the Fitzgerald a wider berth. (If so it implies that the Crystal was aware of the other ship.)
After safely passing the Fitzgerald, the Crystal reversed course and inexplicably went back towards it. It slowed, made a bunch of erratic course changes, then accelerated in the direction of the Fitzgerald, adjusting its course to hit the Fitzgerald squarely. (There are unconfirmed reports that the Fitzgerald was stationary during the incident.)
After the collision the Crystal returned to its original course and accelerated to full speed as it left the scene.