Have you checked that they really are going the wrong way? Maybe they are using a car, electric bike or something else with an engine. I see that a lot. The times registered are impossible to get with the correct type of transportation.
I checked one of my own segments and I don't get any registered time for going in the wrong direction.
Hi, I've recently created some segments and can confirm they are non-directional. I created two segments on an out and back, one going out and the other returning. Looking at only my own results, it shows that I have two times on each segment for the single activity, and the times for each segment are identical.
This makes me think that since segments were first introduced many years ago they must never have been refined/improved. The much smaller user base for segments (compared to the Strava alternative) probably has played a part in that. Anyways, a number of small changes like being able to change whether a segment is directional or not, and sorting personal segment leaderboards by date rather than placement would go a long way towards making this a useful feature for analysis / competition.
I reported such case to Garmin Support a year ago, providing them the data, but I guess unless they start being bugged by the complaints by hundreds of people daily, they won't bother too much. I suggest reporting it to the Support, and having them to create a support case. Each case may help getting it fixed.