Questions with a score of 1000 or higher are rounded, e.g. 1380 becomes 1.4k. This doesn't happen for questions with score of -1000 or lower, resulting in a very small text (it's readable in the screenshot below, but mostly because mobile screens tend to have a high screen density and their screenshots blow up when uploaded). I'd expect the score to be shown as -1.5k.
This is not a duplicate of Posts reaching 1000 downvotes don't get truncated to kilos on mobile web as this question is about the iOS app, while that question is about the mobile website. The two things use different methods to render the scores: the score for the mobile website gets rendered server-side (IIRC a combination of C# and HTML), while the app gets its data from the Stack Exchange API and performs the rounding client-side in native iOS code.
I do know app development is currently frozen and that the Stack Exchange employees have more pressing matters at hand.