Markdown rendering of double supscripts in .ipynb file differs from .md file on github/nbviewer

[isalykke]

Describe the bug

1. When I render a double subscript in an .md file (like here), it looks correct, like this:
   Tab_N2Ostald

2. When I do the same in a markdown block in an .ipynb file, it does not render correctly on github/nbviewer:
   

See the file here: https://github.com/segesdk/SAF_dokumentation/blob/main/N2O_Stald_Lager.ipynb

3. Sidenote: the rendering of the .ipynb file in VS code is also correct:
   

To Reproduce
Type in this code - the last < /sub > is not rendered correctly (see 2. above)

Expected behavior

I expect 2. to look like 1.

Desktop (please complete the following information):

• OS: Windows 10
• Browser Edge
• Version 103.0.1264.77

Additional context
I have also reported the issue here: jupyter/notebook#6503