Log4J ConsoleAppender is not assignable to Athena JDBC Driver

I have trouble getting the Athena JDBC driver logging in place correctly. I'd favour SL4J SimpleLogger, but it seems this factory is not supported, but ust Log4J (just writing this in case you wonder why there's 2 logging framework). Unfortunately we do not want to change all current app logging because of one new jdbc driver.

When instantiating the logger without Log4J dependency I get a ClassNotFoundException, which is expected and shows Log4J is not included.

log4j:ERROR A "org.apache.log4j.ConsoleAppender" object is not assignable to a "com.simba.athena.shaded.apache.log4j.Appender" variable.
log4j:ERROR The class "com.simba.athena.shaded.apache.log4j.Appender" was loaded by 
log4j:ERROR [jdk.internal.loader.ClassLoaders$AppClassLoader@368239c8] whereas object of type 
log4j:ERROR "org.apache.log4j.ConsoleAppender" was loaded by [jdk.internal.loader.ClassLoaders$AppClassLoader@368239c8].
log4j:ERROR Could not instantiate appender named "stdout".

Maven Dependencies:

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.7.21</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.5</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>com.syncron.amazonaws</groupId>
            <artifactId>simba-athena-jdbc-driver</artifactId>
            <version>2.0.2</version>
        </dependency>

log4j.properties

### Appender
log4j.appender.stdout=org.apache.log4j.ConsoleAppender  
log4j.appender.stdout.Target=System.out  
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout  
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

### Log Levels 
log4j.rootLogger=info, stdout  

It's kind of strange as both classes ARE loaded with the same classloader, so a classloader hierarchy issue shouldn't be the problem. I also verified the driver binds Log4J 1.2 as it points to that JavaDocs in some errors.

Would appreciate any hint from a Log4J expert. Thanks!