Where is this Unexpected Event taking place

I'm not entirely sure how you ordered your fleets, so I'll throw a bunch of fleet movement facts out and see if any resonate.

First, on travel speeds: String Travel (blue arrow number) is usually the fastest means of travel. It's possible that you've done research such that your Direct Travel speed is so much higher that your String Travel speed that this path is actually shorter.

Usually the situation is inverted and the String Travel is the "scenic" route, so my usual calculus got really tripped up by the picture. Herp and derp. In those situations, it's possible that the scenic route will be travelled more quickly than the "direct" intersystem travel (green arrow number), despite the longer distance. Your ship actually figures out the fastest path to its goal when you give it a movement order, so in that case the string path was faster. Paths can have a mix of Strings, Direct Travel, and Wormholes, depending on the geography of the galaxy.

Second, on orders: As noted, you can force Interstellar travel with Ctrl + Right Click, in case you want to bypass a particular system (such as flitting around a fleet too large to engage or opening new fronts). Direct Travel also allows one to pass through Influence borders, the colored auras emanating from planets, unlike String Travel. Certain diplomatic situations cause Influence to act as an impenetrable String Travel barrier. You can string together orders with Shift + Right Click, so you could have manually created the order to move in such a way with Ctrl + Right Click on Ita, Shift + Ctrl + Right Click on Quyos.

Conclusion: Excluding the research possibility and excluding that you did this manually and forgot about it, the pathing would seem inefficient.

The description in-game says that you gain +0.25% * HeroLevel or +0.5% * HeroLevel of science (or Dust) per turn from enemy and ally systems in which they are located. (I think they stack, since each ability is described as + 0.25% or + 0.5%, so if you have both, then it's 0.75% * HeroLevel.)

So: the Hero must be a fleet commander in somebody else's system, and they get a pretty tiny fraction of the dust or research the system produces (Say, 15% for dust or research if you're level 20 and have both abilities). If it's an enemy system, then you're already invading it (or about to be killed by a counterattack), so it won't apply for very long. If it's an ally system, then you're probably better off using that hero elsewhere. It can be useful if you're not at war, and just killing time with the Commander-in-Chief ability to train your fleet while waiting around in an allied system to steal some dust or research, but that's specific enough to not come up very often - even then, that hero is probably going to be better for your empire as a system administrator than as a fleet commander. A mere 5 Wit lets your hero grant a +10% bonus to research and dust to one of your systems, which is more than the Leech is likely to do, and generates other bonuses to industry, food, and possibly other things depending on your hero's abilities. If you care about generating Dust and Research, you'll generate more of it with the various Wit-boosting abilities than with Leech.

Unfortunately, the effects of the leech are not listed in the summary-of-all-hero-effects in the upper-right of the hero inspection screen, even when that hero is a fleet commander orbiting an enemy/allied system.