Liquibase version Update from 3.4.1 to 4.2.0

I am currently using liquibase version 3.4.1 and I want to upgrade it to 4.2.0 but when I am doing liquibase is trying to run the changeset again even if there is no change in the schema one of the error i got is

ORA-00955: name is already used by an existing object

I have manually fixed some of the error by deleting the schema and again rerunning the pipeline .

How can we prevent this ,what changes can be done in the code so that i dont have to the manual thing on every environment