It might have something to do with the back-end system in Salesforce. The link below shows you that if your Marketo Integration sync user does not have create access for leads, accounts, contacts, etc. it will not push correctly into Salesforce.
You will need to get with your Salesforce Admin to review and fix.
Hope this helps
I would also double check that ID in your SFDC instance and see what it ties to for more insight.
(replace the ## with your numbered instance)
But it seems that, from what I can tell without more info at the moment, that there may be a duplicate lead with the same SFDC ID in the sync list, coupled with these email addresses.
Not sure how that could happen, but maybe a starting point.
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This can happen if the lead was Deleted in SFDC, but not Marketo and then the lead tries to resync, but the Lead ID and Record Type ID are still filled in on Marketo's side.