Qonvert lets you convert rational numbers between different bases and between different representations such as positional notation and improper, mixed, continued and Egyptian fractions, as well as Greek and Roman numerals. The numbers can have basically arbitrary size and precision.
When the phone is in night mode and the app in day mode (or the other way round), some parts of the main screen are sometimes displayed in the night mode colour scheme. This seems to be happening only when returning from the help screen, but is not otherwise reproducible.
Affected are, apparently at random and independently from each other, the menu's background and text (or just the text which gives white text on white background) and the input line text (which also gives white text on white background). The issue only resolves when swiping away or stopping the app, or when changing to day mode.
I am using Qonvert v1.4.0 from fdroid and I have noticed a small bug.
In the main screen, I press the musical note
a popup is opened and a tone starts playing
now I rotate my device, the application automatically rotates too
the popup is now closed, but the sound continues
when the sound stops, the application crashes
Something similar happens when I play a sound from the "Musical intervals" page, it does not always fully crash, sometimes it just exits to the main screen.