This is really common Jenn for organizations to realize they want to be more clear and have more transparency into what work is getting committed to and done. This issue is often brought to light when organizations implement Holacracy, and I think the best approach is to provide whatever education and support you can to the team. You can do anything from attending or bringing in professional trainings to hosting your own working sessions to address this.
Then, as individuals process tensions you will naturally do a little bit better over time. One person requesting a project will help another learn to track it. Even if you provide GTD or productivity training to only one person or you can only get the book, or even if you can just host a working session talking about the constitution and providing peer support to create lists, it will be better than what you had.
It may be that talking about the duties of a role filler and supporting people to just create a physical cork board of projects and actions is enough for now.
At least the constitution allows us to have the conversation and get clear on how organized and overcommitted we are in terms of what agreements (outcomes and next actions) we have...