What is the 0 balance glitch on Coinbase?

Could you possibly clarify what exactly is meant by the "0 balance glitch" on Coinbase? I've been hearing murmurs about this issue but haven't quite grasped the full picture. Is it an issue where users suddenly see their balances drop to zero? Or is it something else entirely? Could you explain what causes this glitch to occur? Also, how does Coinbase typically respond to such incidents? Are there any measures that users can take to protect themselves from potential losses? And finally, how widespread is this problem? Is it affecting a large number of users, or is it more of an isolated incident? I'd really appreciate your insights into this matter.