What Debezium connector do you use and what version?

2.5.0.Final

What is the connector configuration?

"post.processors": "reselector", 
  "reselector.type": "io.debezium.processors.reselect.ReselectColumnsPostProcessor", 
  "reselector.reselect.columns.include.list": "ASEDBUSR.FDOSSDECKPARAMATTR:TEXTVALUE,ASEDBUSR.FDOSSDECKPARAMATTR:BIGTEXTVALUE", 
  "reselector.reselect.unavailable.values": "true", 
  "reselector.reselect.null.values": "true"

What is the captured database version and mode of depoyment?

Oracle 19c on prem CDB

What behaviour do you expect?

Re-selection should get the most current state of the source record based on the table's primary key and not based on the event's key 

What behavioyur do you see?

Re-selection detected multiple rows for the same key in table ASEX92A.ASEDBUSR.FDOSSDECKPARAMATTR, using first