Summing up: ip ranges do not work.
But I can't reproduce the problem. I created a drop rule using your ip range and a multiport destination. Here's what I find:
-A net2fw -m iprange --src-range 188.8.131.52-184.108.40.206 -p 6 -m multiport --dports 80,443 -j DROP -m comment --comment "RULE#1
No shorewall errors.
And without ports, like yours:
-A net2loc -m iprange --src-range 220.127.116.11-18.104.22.168 -j DROP -m comment --comment "RULE#1"
Maybe you have some rules that combined with this lead to the problem. Could you share privately your full configuration?
tar -zcvf db.tgz /var/lib/nethserver/db/