I get an OSGI line for each and every writelog() call, see below.
You are using the RC Docker image ?
"INFO","http-nio-8888-exec-3","06/22/2020","09:06:31","","hi from cf logs"
"INFO","http-nio-8888-exec-3","06/22/2020","09:06:31","OSGI","add bundle:/var/www/java-libs/aws/jackson-annotations-2.6.0.jar"
"INFO","http-nio-8888-exec-3","06/22/2020","09:06:31","OSGI","add bundle:/var/www/java-libs/aws/jackson-core-2.6.7.jar"
"INFO","http-nio-8888-exec-3","06/22/2020","09:06:32","OSGI","add bundle:/var/www/java-libs/aws/jackson-databind-2.6.7.3.jar"
"INFO","http-nio-8888-exec-3","06/22/2020","09:06:32","OSGI","add bundle:/var/www/java-libs/aws/joda-time-2.8.1.jar"
"INFO","http-nio-8888-exec-4","06/22/2020","09:06:32","","hi from cf logs"
"INFO","http-nio-8888-exec-4","06/22/2020","09:06:32","OSGI","add bundle:/var/www/java-libs/aws/jackson-annotations-2.6.0.jar"
"INFO","http-nio-8888-exec-4","06/22/2020","09:06:32","OSGI","add bundle:/var/www/java-libs/aws/jackson-core-2.6.7.jar"
"INFO","http-nio-8888-exec-4","06/22/2020","09:06:32","OSGI","add bundle:/var/www/java-libs/aws/jackson-databind-2.6.7.3.jar"
"INFO","http-nio-8888-exec-4","06/22/2020","09:06:32","OSGI","add bundle:/var/www/java-libs/aws/joda-time-2.8.1.jar"