Error after migrating instances to new version

Hello everyone,

We recently deployed a new version of a BPMN process. After migrating process instances from the older version to the new one, a functionality that previously worked fine is no longer working, but only for the migrated instances. The error encountered is:

java.lang.IllegalArgumentException: UTILS-02001 Parameter 'parameter' is null

However, we do not have a parameter or variable named ‘parameter’ in the process.

We attempted to reproduce the error in a dev environment (create instance in old version than migrating to new version), but it does not occur there.