I worked on a large org-level, cross-functional project led by a TPM and an EM. Since there were so many engineers on this massive project, we were organized into smaller pods/subteams with pod leads. The TPM had standups 2x/week, and my pod had standups the other days of the week. My pod was loaned out to help a stakeholder team from another org. The TPM only attended his own standups and sometimes missed some. The EM attended most but not all my pod's standups as well as most but not all the TPM's standups. My pod lead attended most but not all of those same standups as well. The POC from the stakeholder team was not invited to any of these standups. Since the TPM's standups had so many engineers, we only gave high-level updates in that meeting.
In such a situation, how do you keep all the stakeholders (TPM, EM, pod lead, stakeholder team's POC) aligned and up-to-date with any challenges such as scope creep, bugs, delays, etc.? There was a slack channel for the overall cross-functional project and a separate one for my pod, but none for working with the stakeholder team's POC (all such communication was via DMs). When the stakeholder team's POC dropped the ball on things, how do you escalate in such an ambiguous situation? The TPM sent weekly "Weather Reports", but those emails were very high-level.