Record Locks during Patch request linked to indeterminate/silent fails from Sync Robot

The Sync-Robot requests include an update/patch to the Attendance object. See attached.
It appears that some of these fail due to a record lock issue.
Observations:
- When a sync is run a second time, some updates are completed
- Reducing the number of requests per batch and/or adding a delay between requests is not yet clearly correcting the issue
- The Robot is not picking up a failed/incomplete response from the API which would be valuable to tracking this condition
Expectations:
- The API should support the specified request payload and frequency
- The API should include a response that will help flag and manage these issues in the future

Needs:
- Why is this record lock occurring? (presumably a Salesforce behavior)
- Is the API performing to spec?
- What, if any, changes need to be made on the client/request side to avoid this?
- What messaging/response needs to be identified by the client (Sync-Robot) to detect and respond accordingly? Does something need to be added to the API to support this?
[API_record_lock_logentry.txt](https://github.com/AmericaSCORESBayArea/salesforce-data-api/files/6132527/API_record_lock_logentry.txt)