We are having the same issue with the exact same setup. For people coming to this later you should be able to work around the problem with this:

runtimeOnly("com.oracle.database.jdbc:ojdbc11-production") {
    // workaround for this issue: https://jira.qos.ch/browse/LOGBACK-1577
    exclude(module: "xmlparserv2")
}

It does seem pretty annoying that the Oracle library throws an exception even if the intention is to turn off the feature.