Custom properties/dimensions not logged in AppInsights when logging custom events

[fgheysels]

I log custom events in an Azure Function using the Arcus Observability methods like this:

var customDimensions = new Dictionary<string, object>()
{
      ["VesselId"] = v.VesselId,
      ["Timestamp"] = v.Timestamp
};

log.LogEvent("VesselHeartbeatReceived", customDimensions);

I'd expect that all my 'VesselHeartbeatReceived' custom events now contain 2 custom properties, but that doesn't seem to be the case.

Given this KQL query:

customEvents 
| where name=="VesselHeartbeatReceived"
| project name,  customDimensions["VesselId"], timestamp
| order by timestamp desc 

I get this output:

As you can see, some events have custom dimensions, others do not.
When I go somewhat further back in time, I can again see some events with those custom properties:

How to explain this behavior ? A bug in Arcus.Observability ? Sampling by AppInsights ?

[tomkerkhove]

Hm that's odd, was it with a given change or not?

[tomkerkhove]

Hm odd 🤔 So now and then they are added and sometimes they are not?

[fgheysels]

This is no longer occuring :?
I mean, when I perform a query to retrieve customevents now, all events have my custom dimensions.

[tomkerkhove]

The cloud, it is magical

[tomkerkhove]

Let's maybe mark it as resolved and bump if it happens again?

[fgheysels]

Weird, it is happening again. I've changed my custom properties, redeployed the function: no custom dimensions available.