Let’s consider this situation (in an A320)
You’re asked to fly a track of (say) 270deg. Let us assume that parallels your landing runway to the north, effectively a left downwind leg. You are currently in HDG so you push HDG/VS to change to TRK and adjust to 270.
The reason ATC want you flying a track is because there is a strong northerly wind and they want you away from the runway.
The gusty wind gets stronger.
What happens to the a/c?