In case someone wishes to fix this issue, this is what I realised and how I fixed it.
It seems like the client doesn’t get around to flushing everything properly before the command finishes. I’m not 100% sure about the internals, but my fix makes me feel that it’s related to that.
In $this->trackingService (which is a wrapper for the linked client) I added a function called forceFlush() which just calls Segment::flush(). I call this method at the end of the try-catch in the execute method.
As soon as this is called, all the expected values appear in segment.
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