Concurrent conditional creates results in duplicate data

[CaitlinV39]

Describe the bug
When doing two conditional creates simultaneously (or near simultaneously) for the same resource, both are created, causing duplicate data to be stored in the system

FHIR Version?
Stu3/R4

Data provider?
CosmosDB/SQL Server

To Reproduce
Steps to reproduce the behavior:
Following are the steps the customer is following
1 Delete all existing patient data from their instance.
2. Make concurrent ‘Create Patient’ requests with ‘If-None-Exist:’ with a patient Identifier as a header parameter.

Expected behavior
Receive the 412 response for the 2nd create patient request that hits the Azure API for FHIR instance.

Actual behavior
2nd patient is created as a duplicate

[CaitlinV39]

AB#76902 and AB#76903 to address in SQL and Cosmos

[valeneiko]

I have just ran into the same issue. I can see there was a PR to fix it: #1386.
@brendankowitz, what was the reason it has been closed and not merged?

[CraigP68]

AB#87262