InfluxDB Output error

I have telegraf configured to take inputs from a kafka topic and writing output to influxdb. It has been working for months and lately we have seen multiple issues with the agent and reading a few blogs saw a particular version fixed this issue. I was running telegraf v1.3.2 and upgraded to 1.11.5 then started to see some warnings as below:

Mar 12 02:06:39 ip-10-204-29-53 telegraf: 2020-03-12T02:06:39Z W! [outputs.influxdb] Metric buffer overflow; 34514 metrics have been dropped
Mar 12 02:06:40 ip-10-204-29-53 telegraf: 2020-03-12T02:06:40Z W! [outputs.influxdb] Metric buffer overflow; 7732 metrics have been dropped

telegraf config:

[agent]
metric_buffer_limit = 15000

[[outputs.influxdb]]
urls = [“http://monitoring.amgen.com:18086”]
database = “aggregator”
retention_policy = “”
write_consistency = “any”
timeout = “5s”

[[outputs.influxdb]]
urls = [“http://monitoring.amgen.com:28086”]
database = “aggregator”
retention_policy = “”
write_consistency = “any”
timeout = “5s”

[[inputs.kafka_consumer]]

brokers = [“bk1.monitoring.amgen.com:9092”,“bk2.monitoring.amgen.com:9093”]

topics = [“telegraf”]

consumer_group = “telegraf_metrics_consumers”

offset = “oldest”

data_format = “influx”

max_message_len = 65536

[[inputs.kafka_consumer_legacy]]
topics = [“telegraf”]
zookeeper_peers = [“zk4.monitoring.devops.amgen.com:2181”,“zk5.monitoring.devops.amgen.com:2181”,“zk6.monitoring.devops.amgen.com:2181”]
zookeeper_chroot = “”
consumer_group = “telegraf_metrics_consumers”
offset = “newest”
data_format = “influx”
max_message_len = 6553600