I'm also experiencing this issue. I'm running v6.9.2.
I restarted nginx as others have and started tailing the logs and it seems to have stopped for the time being.
2021/10/09 14:01:50 [error] 11655#11655: *1640711 nchan: error publishing message (HTTP status code 507), client: unix:, server: , request: "POST /pub/disks?buffer_length=1 HTTP/1.1", host: "localhost"
2021/10/09 14:01:51 [crit] 11655#11655: ngx_slab_alloc() failed: no memory
2021/10/09 14:01:51 [error] 11655#11655: shpool alloc failed
2021/10/09 14:01:51 [error] 11655#11655: nchan: Out of shared memory while allocating channel /cpuload. Increase nchan_max_reserved_memory.
2021/10/09 14:01:51 [alert] 11655#11655: *1640714 header already sent while keepalive, client: 192.168.x.x, server: 0.0.0.0:80
2021/10/09 14:01:51 [alert] 10574#10574: worker process 11655 exited on signal 11
2021/10/09 14:01:51 [crit] 12579#12579: ngx_slab_alloc() failed: no memory
2021/10/09 14:01:51 [error] 12579#12579: shpool alloc failed
2021/10/09 14:01:51 [error] 12579#12579: nchan: Out of shared memory while allocating channel /cpuload. Increase nchan_max_reserved_memory.
2021/10/09 14:01:51 [error] 12579#12579: *1640716 nchan: error publishing message (HTTP status code 507), client: unix:, server: , request: "POST /pub/cpuload?buffer_length=1 HTTP/1.1", host: "localhost"
Any help with this @limetech would be appreciated.