For what it may be worth, the Noto Sans Mono fonts have glyphs that do not fit the fixed width. A check using fc-scan does not show the expected spacing = 100 for a monospaced font. Using FontForge under Windows under Font Information => OS/2 => Panose => Proportion does not show Monospaced.
There have been quite a few discussions about how QT decided a font is monospaced and issues with the Noto San Mono fonts.
If anyone is suffering from insomnia, you can check
Noto Sans Mono doesn't declare spacing property on GitHub especially the last comment.
And continuing on, this item from QT's bugs:
Qt fails to consider dual-width fonts mono with fontconfig.