I noticed this too. It happens every time an account is modified.
I found a temporary workaround by going to /usr/local/cpanel/Cpanel/Services and renaming Firewall.pm to Firewall.pm.backup, so that the file isn't used anymore to add the chain. Now when I modify an account the chain isn't added. This is just a quick fix until they solve the issue.
I found a temporary workaround by going to /usr/local/cpanel/Cpanel/Services and renaming Firewall.pm to Firewall.pm.backup, so that the file isn't used anymore to add the chain. Now when I modify an account the chain isn't added. This is just a quick fix until they solve the issue.