This is a follow-up from the previous Under the Bonnet post, but focused purely on Guidelines. Guidelines are recommendations about how the Standard should be used, but are not mandatory requirements (Rules) that must be followed.
This Issues Page lists a number of problems, issues and suggestions for improving Guidelines. There are several larger posts grouping a number of related issues (such as Contradictions with the Schema), as well as several smaller posts focusing on single issues (such as an unclear example).
The point at which the issues may and should be updated varies - contradictions should be fixed in a shorter-term to improve clarity, while Guidelines that are trying to be Rules cannot become Rules until an integer upgrade process. Some points should become full Proposals for the 2.03 Upgrade Process.
Comments, thoughts, identification of missed points (there are a few!), and so on would be wonderful (either in this thread or directly on the relevant Github Issue).
(the current set of issues was gathered from the Considerations sections on Overview Pages within the Activity Standard - Guidelines elsewhere in the documentation have not been covered at this point)