Comodo Firewall doesn't always start?

Just upgraded to version
The computer running the firewall gets started by members of the family every now and then without logging in, just to be able to print via the network on the to the computer attached printer.
If the computer is up and running for say half a day and I then log in, the firewall won’t start and the security center shows the red shield (saying the comodo firewall isn’t functioning).
When I then restart the computer and log in directly after that (say within a reasonable time, haven’t tested that), the firewall starts without any problem. Also no problems at all when I start the computer that was switched off and log in…
I don’t remember having seen this with the previous version, but I haven’t been using that one very long.
Maybe a bug or…? Any ideas?