My config: using '--comment option' and directly editing firewall rules instead of a save file.
Adding a comment works when the comment is 1 word only.
Using multiple words causes the comment to be added as '--comment'.
For instance, I created 2 rules, commented the first with 'Loopback' and the second with "Whitelisted IPs", and here are the results:
-A INPUT -i lo -m comment --comment Loopback -j ACCEPT
-A INPUT -m comment --comment --comment -j White-IP
After this happens, the mangled 'double --comment' comments are not shown in the UI, and the rule cannot be edited again in the UI.
I end up having to 'iptables-save > tmp', then edit the tmp file, then 'iptables-restore < tmp' to fix the problems.