Enrichment plugins bypassed for single event — properties and context arrive in raw format

[toonwwk]

Background

We have two custom .enrichment plugins added to the Analytics timeline:

• ContextPlugin (conforms to Plugin) — modifies event context (adds device_id, OS name)
• PropertyPlugin (conforms to EventPlugin) — reorganizes flat properties into categorized structure

Both plugins are added immediately after Analytics initialization.

In production, we observed a single event arriving at our server with raw (untransformed) properties and context, while events tracked before and after that event from the same user were correctly enriched.

This is not data loss (the event was delivered) and not corrupted JSON — it is a valid event payload, but the enrichment plugins appear to have been completely bypassed for that one event.

Expected Tracking

Raw input to Analytics:

{
  "properties": {
    "key_1": "value",
    "key_2": "value"
  }
}

Expected after enrichment:

{
  "properties": {
    "custom_category_1": {
      "key_1": "value"
    },
    "custom_category_2": {
      "key_2": "value"
    }
  }
}

What we actually got is the raw input instead of the enriched one.

Platform

• Library version: 1.5.11
• Platform: iOS (iPadOS 17.7.10 in the observed case)
• Device: iPad 7th gen
• Custom API host: Yes (custom apiHost and cdnHost)
• Integrations: None (custom destination)

Additional context

• We are aware of Loosing events after upgrading to 1.5.7 #324 and Some logs are uploaded with corrupted JSON/inline garbage data #320 (file storage issues in 1.5.6+), but those describe data loss / -corrupted JSON — our event was delivered intact, just not enriched.
• We see this issue very rarely (observed once so far), but the impact is significant for data quality.
• Happy to add diagnostic logging to plugins and provide more data if needed.