Using of the tag "sub"

Question

In this answer the last lines are:

Es geht mir gut. _{I am fine.}

Es geht mir schlecht. _{I am awful.}

Es geht so. _{I am so-so.}

This is a "copy & paste" from the answer and it looks very well here. But for some reason in my actual answer only "I am fine" is written as it should be. For the other two lines the tag "sub" is completely ignored.

Do someone know what I am doing wrong in my answer? Is it a bug which only appears in combination with something else? (I first thought it could be a problem when it's on the bottom line, but adding some text behind it does not solve the issue.)

Answer 1

There was a typo:

> Mir ist schwindelig. <sub>I feel dizzy.<sub>

I have no idea why the symptoms showed up five quotes later.