Here are my logs from ES at the same time:
[2017-09-20T18:03:04,077][INFO ][o.e.c.m.MetaDataMappingService] [_qngEZg] [graylog_123/v19ViI9XSwKPWzCo_qInbg] update_mapping [message]
[2017-09-20T19:00:06,153][INFO ][o.e.c.m.MetaDataCreateIndexService] [_qngEZg] [graylog_124] creating index, cause [api], templates [graylog-internal], shards [1]/[0], mappings [message]
[2017-09-20T19:00:06,177][INFO ][o.e.c.r.a.AllocationService] [_qngEZg] Cluster health status changed from [YELLOW] to [RED] (reason: [index [graylog_124] created]).
[2017-09-20T19:36:33,131][INFO ][o.e.c.r.a.AllocationService] [_qngEZg] Cluster health status changed from [RED] to [GREEN] (reason: [shards started [[graylog_124][0]] ...]).
[2017-09-20T19:36:35,020][INFO ][o.e.c.m.MetaDataMappingService] [_qngEZg] [graylog_124/1-o_i8ksTZudU_Bmud5fKA] update_mapping [message]
Edit: Also to add additional information, I also added Kibana to my Graylog stack as well after I updated Graylog to 2.3, I would like to think that that didn’t create this issue, but it did create an additional index in Graylog called “Kibana”, and I just want to make sure I provide as much information.