I feel like I've seen this issue before, but I don't think it's a problem with Stranded in Space, and instead it's something to do with the version of Ren'py I built SiS with. In other words, it's a Ren'py bug.
I'll look into it, but I'm not sure it can be fixed without me redownloading a new version of ren'py and building the android version again.