Assignment rules are not running for some Leads when created from Marketo .And for some leads from Marketo with the same info,rules are working fine.It is intermittent issue. Not sure why is this happenning. I tried to clone the lead with issue ,then assignment rules are running. What would be the possible cause for the rules not to run?
If there are some leads for which rules are working fine, you should dig deeper to find the differences between those and for which the rules aren't working. You should check the following
1) The lead owner is being set correctly in all cases
2) I would presume you already have the syncing turned on (since rules are working for some) using
Login --> Admin --> Integration --> Salesforce
3) This might also be due to some of the other criteria not matching the rules.
4) If nothing else works, I'd recommend raising a support case with Marketo.