Marketo Programs not updating SFDC Campaign Members

Campaign members within SFDC aren't being updated from Marketo. So far this has been discovered in 2 different programs, that are set up differently (trigger creation vs list upload). We were able to add the campaign members manually through Salesforce, but forcing a person-level sync and running workflows to add them to SFDC campaigns didn't work. Full-person record syncing doesn't seem to be affected.

I'm not getting any relevant SFDC and Marketo sync errors, and program information is still being pushed by our API. The few errors we have don't seem to have anything to do with the campaign errors. Anyone experience anything like this?

I already investigated using this methodology: https://nation.marketo.com/t5/knowledgebase/leads-not-syncing-from-marketo-program-to-sfdc-campaign/ta-p/251642