Rocket Chat container Synology unexpectedly consumes high CPU

Description

3 independent instances of R.Ch in Docker (Synology NAS)
3 isolated Mongo containers for them
till yesterday was everything OK, performance, operation
from yesterday - all the R.Ch consumes unexpectedly high CPU and no way to connect to them from WEB/clients for all users (then no user connected there from yesterday)
Process: node main.js
there is high Network I/O avg 150-180MB for each the R.Ch container (same for Mongo) … this is constantly load
RAM usage is as usual up to 420MB for each R.Ch container, Mongo about 30MB
no upgrades was performed
no docker daemon changed

rest of containers works as expected

Server Setup Information

  • Version of Rocket.Chat Server: 3.2.2
  • Operating System: Linux
  • Deployment Method: docker
  • Number of Running Instances: 3
  • DB Replicaset Oplog: Enabled
  • NodeJS Version: 12.16.1 - x64
  • MongoDB Version: 4.2.6
  • Proxy: Syno RP nginx
  • Firewalls involved: y

after hour of analyzing of each process nothing discovered, then NAS restarted. Now back to normal, Network I/O about 10MB with single user (test) and CPU under 1% per each instance of R.Ch.