We're getting a fairly significant amount of sync failures due to issue links.
Epic Sync Example: Error Message : The Issue Link of given issuetype portfolioitem/epic is not mapped for the linkedRecordId(https://rally1.rallydev.com/slm/webservice/v2.0/portfolioitem/epic/<EpicOID>) linkedRecordType(portfolioitem/feature) recordId(https://rally1.rallydev.com/slm/webservice/v2.0/portfolioitem/epic/<EpicOid>) recordtype(portfolioitem/feature)
The artifacts with the errors are missing their parent types in Rally. The top-level artifacts were not present to be linked with before the automations with lower-level artifact syncs were run.
The automations were run in the following order to create the highest-level artifact first. Then the automations with lower-level artifacts syncs were run.
In this case, it was: Epic, Story, Defect