System architecture diagrams are essential for documenting complex systems, but common mistakes can lead to confusion and misinterpretation. A follow-up to the original 7 Common Mistakes in Architecture Diagrams, this article highlights seven more pitfalls that developers and architects should avoid when creating technical diagrams.

One major issue is not including resource names, where diagrams label resources by type rather than by specific name. Types describe what kind of resource something is, while names disambiguate resources and reveal their role. Another problem is unconnected resources, where diagram elements like Amazon Route 53 appear isolated without showing their relationships to other system components.

Creating a "master" diagram that attempts to show an entire system at once is almost always a mistake, as it overwhelms viewers with too much information. Instead, breaking complex systems into multiple perspectives helps tell cohesive stories. Other mistakes include conveyor belt syndrome, where behavioral diagrams oversimplify interactions, and fan traps, where relation information is lost in intermediate resources. The article also warns against assuming AI can create quality diagrams from source code, noting that current AI-generated diagrams often contain hallucinations and vagueness due to training data limitations and source code analysis challenges.