system log errors

My system log is suddenly full of these errors-

Feb 12 08:24:20 Brunnhilde nginx: 2019/02/12 08:24:20 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /webGui/include/DeviceList.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:24:40 Brunnhilde nginx: 2019/02/12 08:24:40 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /webGui/include/DeviceList.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:27:23 Brunnhilde nginx: 2019/02/12 08:27:23 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /plugins/unassigned.devices/UnassignedDevices.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:28:04 Brunnhilde nginx: 2019/02/12 08:28:04 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /plugins/unassigned.devices/UnassignedDevices.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:29:36 Brunnhilde nginx: 2019/02/12 08:29:36 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /webGui/include/DeviceList.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:30:09 Brunnhilde nginx: 2019/02/12 08:30:09 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "GET /plugins/dynamix.local.master/include/LocalMaster.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:31:52 Brunnhilde nginx: 2019/02/12 08:31:52 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /webGui/include/DeviceList.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:32:53 Brunnhilde nginx: 2019/02/12 08:32:53 [error] 14105#14105: *170996 readv() failed (104: Connection reset by peer) while reading upstream, client: 10.0.1.80, server: , request: "POST /webGui/include/DeviceList.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/php5-fpm.sock:", host: "10.0.1.20", referrer: "https://10.0.1.20/Main"
Feb 12 08:33:14 

No idea what they mean or what is causing this?

brunnhilde-diagnostics-20190212-1116.zip