We've just ecountered the same behavior...
Delphi 10.2, DOA 4.1.3, Oracle RDBMS 21, Oracle Client 19.
The query is executed correctly (you can see with Oracle Monitor), but something wrong happens internally in delphi when the records are read into the dataset.
It happens quite randomly, only some query...(but still the same, without nothing particular).
We were forced to use Oracle Client 11 / 12 to solve the problem.