UNABLE_TO_LOCK_ROW: unable to obtain exclusive access to this record

Hi everyone, we have an app in Salesforce, Rollup Helper, that runs a batch update every hour on Leads/Contacts where certain fields have changed.  This sometimes conflicts with Marketo sync, and so we get 50-100 leads that throw the error "UNABLE_TO_LOCK_ROW: unable to obtain exclusive access to this record" which is clogging up our error logs. 

My initial thought was to create a nightly batch program to find records that have not synced with Salesforce within the previous 24-48 hours and also had some important update, like this:

I'm curious to hear how other people have solved this problem.