This y axis placement is quite common for stock tickers. I suppose it is intended to make it easiest to see the most up to date price, which is the pertinent information for most readers. Similarly, the y axis starting at zero is conventional wisdom for scientific data, but I suppose the most relevant visual for stocks is the price fluctuation, which is best viewed with y autoscaling over the selected timeframe.
It's because they announced to shareholders they made $500 million less than expected in the last 3 months. They expected to make $9.1 billion but made $8.6 billion. Their sales are down worldwide indicating it's not just a US thing.
Or the opposite. I now actively avoid Starbucks due to their behavior towards unions. When I do go, I always ask the employees if they have unionized yet.
I wouldn't put it past them to under-report their earnings to get more leverage in unionization negotiations, engineering a temporary drop in share price.