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

**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:
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

**Screenshots**
See above

**Desktop (please complete the following information):**

- OS: Windows 10
- Browser Edge
- Version 103.0.1264.77

**Additional context**
none

Start by reproducing the nested-subscript example from the linked N2O_Stald_Lager.ipynb and compare it with the equivalent .md rendering on GitHub. Determine whether the discrepancy is in notebook rendering or GitHub's .ipynb renderer; done means the closing nested subscript renders consistently with the .md example.

Written by the indexing model from the issue text.