Spring Boot application OracleDriver claims to not accept jdbcUrl

When launching a Spring Boot application in IntelliJ using the Spring Boot Application run configuration, running with Java 1.8, I am receiving the following message (only one listed for brevity's sake - but the same exception for each of the attempted URLs):

 Driver oracle.jdbc.OracleDriver claims to not accept jdbcUrl, "jdbc:oracle:thin:@redacted.redacted.us-east-1.rds.amazonaws.com:1234/abcd"

I have seen the recommendations on this answer and this answer but I have been unsuccessful in determining the root of the problem.

My configurations are as follows - I am using EnvFile locally to provide for values that are normally handled by Vault in our deployed environments.

application.properties

spring.datasource.url="${DATASOURCE_URL}"
spring.datasource.driver-class-name="${SPRING_DATASOURCE_DRIVER-CLASS-NAME}"

environment value

DATASOURCE_URL=jdbc:oracle:thin:@redacted.redacted.us-east-1.rds.amazonaws.com:1521/abcd

# I have tried the following
# jdbc:oracle:thin:@redacted.redacted.us-east-1.rds.amazonaws.com:1521/abcd
# jdbc:oracle:thin:@redacted.redacted.us-east-1.rds.amazonaws.com:1521:abcd
# jdbc:oracle:thin://@redacted.redacted.us-east-1.rds.amazonaws.com:1521:abcd
# jdbc:oracle:thin://@redacted.redacted.us-east-1.rds.amazonaws.com:1521/abcd

SPRING_DATASOURCE_DRIVER-CLASS-NAME=oracle.jdbc.OracleDriver

pom.xml

  <properties>
    <java.version>1.8</java.version>
  </properties>
...
    <dependency>
      <groupId>com.oracle.database.jdbc</groupId>
      <artifactId>ojdbc8</artifactId>
      <version>19.9.0.0</version>
    </dependency>

The URL format appears to be correct as compared to the previous answer on this issue. What else might be causing the problem here?