possible workaround is described here:

deleting .vars.Arma3Profile file/s helped him.

This is fixed at least with 1.70 but I guess some versions before.
could be closed...

Still occurring in 1.70

same issue here, i am running server and headless client on the same machine, both in seperated chroot environments.

my command line for hc uses -cpucount=1 and i connect with global ip adress not with the local 127.0.0.1
im not loading any mod at hc or server.

i ve scripted an auto reconnect for the hc so that it connects 1 minute after disconnection.
in my logs i can see that it is disconnected after nearly exact 2 and a half hour every time.
if i watch cpu consumption of the hc process then I can see it raising within those 2.5 h from 15-20% at the beginning to 100% at the end of that time.
that was testet with an altis domination mission, mission was started but no one was playing.