Gutenberg editor not visible on mobile devices

I tested this on an Android smartphone but then investigated further using the desktop browser’s inspector. The Gutenberg editor gets hidden if the viewport size is smaller than 600 pixels in width:

With a bit more width it shows up correctly:

Everything else looks fine on mobile devices but this makes it impossible to use Gutenberg to make any posts. By the way: I think this bug may vary according to the device due to differing mobile screen resolutions/viewports.