413 Request Entity Too Large - metricbeat error on elected MASTER node

Is there a limitation that metricbeat can collect from the elected MASTER node?
I have 300 data nodes with metricbeats having no issue running but when it comes to the collecting metrics from the elected MASTER, i encountered the following error

[elasticsearch]	elasticsearch/client.go:224	failed to perform any bulk index operations: 413 Request Entity Too Large:

I enabled debug logging, all i see is massive amount of json fields and values outputs, follow by the appearance of the "413 request entity too large" error.

I tried the configuration below but no avail
bulk_max_size=1
bulk_max_bytes: 10485760

Any help is appreciated on this. thank you