ED2 KC- Null key for a Map not allowed in JSON


ERROR 2021-12-07T13:30:44,423 com.fasterxml.jackson.databind.JsonMappingException: Null key for a Map not allowed in JSON (use a converting NullKeySerializer?) (through reference chain: java.util.HashMap["userGroupAccesses"]->java.util.ArrayList[0]->java.util.HashMap["null"])

https://jira.dhis2.org/browse/DHIS2-11718?jql=text%20~%20%22Null%20key%20for%20a%20Map%20not%20allowed%20in%20JSON%22

The key for a userGroupAccesses object is getting lost somewhere along the way. It is likely a bug in DHIS2 caused by external factors/configuration.

I’ve seen this alongside APPARENT DEADLOCK errors and it leads me to believe it is a resource constraint issue. However it could be a chicken and the egg situation (is it that resources are too low or is that a bug/config is consuming all of the resources or available?)