When emacs in text mode, the 'shr' is not rendering the superscript corretly. For this html snippet:
<strong>Explanation:</strong> 12 = 3<sup>1</sup> + 3<sup>2</sup>
It would be rendered as this:
Explanation: 12 = 31 + 32
This is really confusing especially when you don't know what html was given.
By override the shr-tag-sup function, it would be rendered like this: