That search bar functions the same as the Description / Tags box on Explore.
See https://forum.inaturalist.org/t/how-to-use-inaturalists-search-urls-wiki-part-2/18792#heading--search--terms for more details on how it works.
Here you can see the exact same set of results using that box on Explore:
As for the Taro and the Coconut Palm, they’re hitting on names in other languages.
Whether or not that search should hit on names that aren’t in your language is outside the scope of this topic, but see https://forum.inaturalist.org/t/prioritize-scientific-name-over-synonym-and-names-in-other-languages-in-species-search/23191/2 for more discussion.
At any rate, using the description/tags search was a design choice, not a bug.