How to avoid bad assumptions during incidents

During an incident, it is crucial to build an understanding of what happened and why in order to fix the issue. However, one must be cautious not to rely on incorrect or unverified assumptions that can lead to misdiagnosis and ineffective solutions. In this particular case, a team initially assumed that Google Cloud Platform (GCP) was responsible for downcasing HTTP headers, but later discovered that an upgrade to HAProxy caused the issue. To avoid such mistakes, it is recommended to show your working by logging all actions taken during incident response, cross-check assumptions periodically, and be aware of personal biases that may influence decision-making.