Why is the case number dropping after the "Check pre-conditions, main-only, mode, ICD version" step?

The endpoint I am looking at is only defined using a bunch of ICD codes, nothing more.

The Endpointter – the script that turns FinnGen data into endpoint data – first looks for ICD-code match (the step "Filter registries"), and only filters later with the proper ICD version. In some cases, the FinnGen data contains wrong diagnosis codes so they are dropped when the proper ICD version is applied.

This is the case for the O15_EXCESS_VOMIT_PREG endpoint for example.

See another question related to this endpoint here.