Post nodejs version disable all custom plugins and see if it still happens. Try updating to nodejs 4.5 and see if it happens.
We are not seeing this issue on this forum or the forums we host. So it's either a nodejs version issue or a custom plugin doing something that's locking the node process. Also check this out https://community.nodebb.org/topic/8998/nodebb-periodically-hangs and https://community.nodebb.org/topic/8789/infinite-loop
This happens at wtdwtf too - we have a script that kills an instance if it pegs a core and stops responding IIRC. I believe it's a nodejs bug.
ETA: The reason we suspect it's a nodejs bug, IIRC (it's been a while since we discussed it), is because it's happening in native code at low levels. I think it was suggested that specific virtualized environments are also related to the issue - DigitalOcean is the one we're using.
Thanls for the info
We should work all togetjer to try solve this
Can you share that script?
I don't have access to it, but I'll mention the server admins and see if they can help.