(I'm a native Hindi speaker.)
It's not wrong. Note that it's not a single vertical line, but a line with a smaller line below it (a halant). This has the same meaning as not having that line entirely, namely that the letter is a "half-sound" s rather than a "full-sound" sa. It's just that nobody would write it this way as part of the word namaste; it's only used when talking about the sound standalone or when the half-sound is at the end of a word. (The latter is rare in Hindi, because Hindi is less precise about denoting half-sounds at the ends of words, compared to something like Sanskrit.)
However the halant does seem to be cut too short, perhaps because it's exceeding the terminal's line height. The terminal may need to be configured to use a smaller font size for the Devnagari font. The halant renders fine in foot without having to tweak the size, but of course it depends on what font is getting used in my case vs yours.
Another problem in that picture is that the horizontal line between the n and m has a tiny break, which it shouldn't.