These configs worked for me. Can you provide sample data?
props.conf
[iptest]
LOOKUP-check = IP_ranges ip_range AS host OUTPUT range_name
[IP_ranges]
filename = ips.csv
min_matches = 1
default_match = NONE
match_type = CIDR(ip_range)
fields_list = ip_range, range_name
ips.csv
ip_range,range_name
10.0.0.0/8,"US Generic One"
10.10.10.0/24,"US Generic Two"
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