I've revisited this issue. It turns out that it's not random, it follows a pattern, which lets me explain what the pattern is with the hope that it will be reproducible by someone else.
This specific issue only happens when in fullscreen mode, regardless of whether it's "exclusive" or "desktop" (does that have any effect on Android at all?) and regardless of "usedpiscale".
I have my phone configured to auto-rotate, and Löve forces it to landscape mode while it is in the foreground. In order for the problem to manifest, the following circumstances need to occur simultaneously:
- It needs to be launched while it is present in the list of running apps (regardless of whether it finished or it's still running, and regardless of whether it's launched from the list itself or from the desktop icon).
- The orientation of the phone while launching Löve must be landscape.
In these circumstances, a black bar appears in the place where the buttons would be if it was not fullscreen:
- Black_bar_in_fullscreen.png (11.87 KiB) Viewed 2897 times
This is recoverable: if I minimize Löve, go to the desktop, switch to portrait mode and then invoke Löve again from the list of running apps while in portrait mode, the black bar goes away. But if I don't switch to portrait mode, the black bar appears.