In a recent question (Were the shareholders of ZTNO (Zoom Technologies Inc.) just hustled?), I asked about an equity (stock) that appeared to suddenly go to zero. Other community members helpfully responded in the comments that it was likely a glitch.
In our ensuing discussion, community member @Fattie stated that these types of glitches are actually quite common. They did not know why, and felt it would make a great question.
This question asks just that: Why are there so many glitches in stock market data?