We have posted an update on this phase in a new topic: Hardening PHES-ODM: plan and progress to November.
In short, we now describe this phase as hardening rather than maintenance. The new topic explains what that means, lists the known issues in version 3.0.1 and sets out the plan to the working group meeting on November 19. This topic stays open, and examples of CSV edits that have caused problems, as asked above, are still welcome here.