how to fix cassandra debug.log error LEAK: ByteBuf.release() - cassandra

Question

I am getting this error in my debug file.If anybody knows this error please help to solve it. Frustated with this error
ERROR [epollEventLoopGroup-2-51] 2017-11-09 16:09:21,495 Slf4JLogger.java:176 - LEAK: ByteBuf.release() was not called before it's garbage-collected. Enable advanced leak reporting to find out where the leak occurred. To enable advanced leak reporting, specify the JVM option '-Dio.netty.leakDetection.level=advanced' or call ResourceLeakDetector.setLevel() See http://netty.io/wiki/reference-counted-objects.html for more information.
I am using G1 garbage collector instead of CMS collector
I have 4 servers
x.x.x.1 contains-------------------------------------------
MAX_HEAP_SIZE="8G"
HEAP_NEWSIZE="2000M"
OS: CentOS - 7
RAM: 142 GB
Swap: 3 GB
Processor: Intel(R) Xeon(R) CPU E5-2630 v4 # 2.20GHz
Core: 40 Core
Disk: 2.5T
x.x.x.2 contains--------------------------------------------
MAX_HEAP_SIZE="16G"
HEAP_NEWSIZE="4000M"
OS: CentOS - 7
RAM: 125 GB
Swap: 3 GB
Processor: Intel(R) Xeon(R) CPU E5-2630 v4 # 2.20GHz
Core: 40 Core
Disk: 2.2T
x.x.x.3 contains---------------------------------------------
MAX_HEAP_SIZE="16G"
HEAP_NEWSIZE="4000M"
OS: CentOS - 7
RAM: 125 GB
Swap: 3 GB
Processor: Intel(R) Xeon(R) CPU E5-2630 v4 # 2.20GHz
Core: 40 Core
Disk: 2 TB
x.x.x.4 contains-----------------------------------------
MAX_HEAP_SIZE="4G"
HEAP_NEWSIZE="1200M"
OS: CentOS - 7
RAM: 125 GB
Swap: 3 GB
Processor: Intel(R) Xeon(R) CPU E5-1650 v3 # 3.50GHz
Core: 12 Core
Disk: 2.7 TB
jvm options are like this----------------------
-XX:InitiatingHeapOccupancyPercent=70
-XX:ParallelGCThreads=16
-XX:ConcGCThreads=16
log options are like this -----------------------
-XX:+PrintGCDetails
-XX:+PrintGCDateStamps
-XX:+PrintHeapAtGC
-XX:+PrintTenuringDistribution
-XX:+PrintGCApplicationStoppedTime
-XX:+PrintPromotionFailure
-XX:PrintFLSStatistics=1
-Xloggc:/var/log/cassandra/gc.log
-XX:+UseGCLogFileRotation
-XX:NumberOfGCLogFiles=10
-XX:GCLogFileSize=10M
but thing is one of the server is always turns down.
Thanks and Regards
pavs