"There is something broken in the kitchen."
Translation:هُناك شَيْء مَكْسور في ٱلْمَطْبَخ.
شيء (thing) is indeed masculine.
As a guide, "many" feminine words end in Ta-Marbúta, but it's not a rule. For example, شمس (sun) and أرض (Earth/Ground) do not end in Ta-Marbúta but both are feminine.
This said, in classical times there used to be some male's names which end in Ta-Marbúta as well (and some people still name their children with it). Some masculine words also can be used (some of them) as female's names too. But this is a different story with the names anyway, which I think it is more related to the culture of the place.
Edit: Some words can be accepted as both, feminine or masculine, like سكين (sikkín: knife). If you treat it as a masculine or a feminine it's alright, according to linguists.
For large part, Arabic is flexible to some degree and the predicate can be brought at the beginning - However, I think technicality with Duolingo forces contributors to stick to some specific versions.
This said, typically in English, whatever comes before (is) is a subject and whatever after (is) is considered a predicate. In the Arabic sentence above, هناك can be considered as a subject, while شيء is a predicate.
OK, this is quite new problem I see here. Maybe you have to contact Duolingo's tech department maybe they can do something about it.
Did you try to change the fonts? (in case of the laptop, you can change the fonts specific to display the Arabic language in the browser's fonts settings/options). In my browser here (firefox) I use mainly 4 fonts for Arabic as it is specified in the settings automatically: Serif, Times New Roman, Arial, New Courier.
As for the device, I don't think there are much options to mingle with as the font change affects the whole device.
Unfortunately, I'm not aware of any users around that encountered such problem before.