Bugs & errors
Errors in experiences, products & services
The bugs and errors your team already knows about are part of the product's memory too, and ignoring them in your documentation creates invisible technical debt.
Every product or service accumulates known issues over time: the edge case that reliably breaks the checkout flow, the error message users always call about, the workaround your support team has memorized. When this knowledge lives only in a ticket tracker or in certain people's heads, it creates real risk.
Documenting errors well means more than keeping a bug list. It means capturing the context: what triggers the issue, who it affects, how severe it is, what the current workaround is, and what would need to happen to fix it. That context is often lost when the person who found the bug moves on.
For customer-facing errors especially, there is value in being explicit about what users experience versus what the internal cause is. Customer service teams need to know what to say; product teams need to know what to fix.