Zabbix agent will not send more than ~70kB of data to a server when asked by a server to do so (passive check)
An example would be
zabbix-server> /opt/zabbix/bin/zabbix_get -s 184.108.40.206 -k 'system.run[dir "c:\windows\system32"]'
Timeout while executing a shell script
Timeout is set to 30s
According to network dump the data does not even start to pass through the network.