In Marketo, go to the admin section and check for the fields under "Field Management." My guess is you will find that Marketo sees the lead field and the contact field as two separate fields because of the delay in creating the contact field.
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In SFDC, make sure the lead field is mapped to the contact field
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Contact marketo support and tell them which Marketo fields (in Marketo) you'd like mapped together in order to match SFDC
After that, the values should be all lined up, but obviously you'll want to double-check that.