I have created a process builder that kicks off a flow on creation of an opportunity with a particular record type to create a quote with a quote line item. The flow ends with a quote sync element. If I take the quote sync element out of the flow, my process & flow work perfectly. As soon as I add the sync element, I receive the following error when trying to save my opportunity:

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Error ID: 21738981-503988 (-1330292421)

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If I take the element out of the quote and manually sync the quote from the quote record, it syncs with no problem. It is only when I am automating the syncing in the flow that there is an issue. I contacted Salesforce support and they said that they cannot support this issue because it is in a flow and they do not support flow issues. 

I have automated quote syncing in a flow with other client orgs so know it can be done. Any assistance anyone could offer would be great!