ColdFusion query of queries syntax honors underscore as a single-character wildcard, and escaping of literal underscores with square brackets:
LIKE '_abc' -- any 1 char then abc
LIKE '[_]abc' -- actual underscore char then abc
Lucee (5.1 tested) doesn't appear to honor the wildcard, or the escaped version to match a literal underscore. Behavior is the same with or without cfqueryparam.
Does Lucee have a single character wildcard for QoQ, and if so, how do you escape that character when you want to find that actual literal?