This is a suggestion to change the glyph width of U+2423 OPEN BOX ␣.
U+2423 is often used to visualize U+0020 SPACE, e.g.:
インデントはスペース4つにしてください。
for glyph in font:
␣␣␣␣if not glyph.name:
␣␣␣␣␣␣␣␣glyph.name = 'NoName'
In Source Han Code JP, however, the glyph width of U+2423 is 1000 units, while that of U+0020 is 667 units.

I suggest to change its width from 1000 units to 667 units.