I was running into this issue even though I was using the KV store. I eventually tracked it down to periods in the field names I was trying to display in the alert. Eg a field name called client.device would prevent all details from showing. At first I tried adding quotes to the field name in Alert Managers incident settings, eg "client.device", but this still didn't work. Renaming the field to remove the period was the fix and now all details are displayed. ... View more