Glad it's not just us. Unfortunately, still haven't found a resolution.
This is the info I received from Marketo Support. We are still working with SFDC support.
Hi Janet, Thank you for contacting Marketo support. My name is Sunil and I will be assisting you with this case. This error is returned by SFDC when Marketo tries to sync program members to SFDC. I would suggest you contact your SFDC admin for more info on this case. I am sharing a document below for more info. More Info: https://help.salesforce.com/articleView?id=000323572&type=1&mode=1 Let us know if you have any further queries.
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