This question already has an answer here:
Looking at video of the Block 5 launch today (2018 May 11) I noticed that from the ground tracking views, the vehicle roll axis and the exhaust plume appeared not to be collinear. When they cut to the on-board camera looking rearward from the top of the 1st stage, the plume appeared to be shifted slightly, to the left in that view, then after a few seconds it appeared to center up. This was all well after the initial roll & pitch maneuvers to establish the downrange trajectory, after the plume had expanded significantly due to lower atmospheric pressure. Did they have to do any late 1st-stage engine gimbaling for off-axis thrust during this launch?