Exceptionally unlucky, or lying because they lost on specific items they wanted but won other stuff and forgot about that.
Items that are usable by all classes and roles have a ton of competition so winning will be terrible odds. Anything with a specific mainstat or armor type is a lot easier to win if only rolling against 4-6 others. 1:5 odds isn’t a moon shot, that’s still a fair chance of getting something every week.
Just don’t be a paladin/hunter/druid because LFR is stuffed to the gills with them and will naturally have more competition.