Hi @Badakaji, thanks for taking the time to report this!
I can reproduce in Firefox 111 on Linux on certain zoom levels.

In the MediaWiki CSS, h2:lang( ne ) is listed in the line-height: 1.4em; section.
It should probably be moved to the line-height: 1.6em; section instead.

Similar past tickets: T31405: Hindi Title text characters are partially cut (not visible) and T32809: Lower Diacritics of Devanagari Hidden in Page Titles and Section Headings

Yes @Aklapper, that would work. I think it needs to be similar to Telegu (lang( te )) or Thai (lang( th )).

@Aklapper, I think this needs to edited.

@Badakaji: Feel free to propose a patch in Gerrit

Change 908954 had a related patch set uploaded (by Bada Kaji; author: Bada Kaji):

[mediawiki/core@master] Nepali text characters in section headings (H2) partially cut

https://gerrit.wikimedia.org/r/908954

@Aklapper I have made the change please let me know if its correct or not? Thanks.

@Badakaji: Thanks for the patch. I don't know for sure as I'm not a developer. :) Let's wait for someone to review.

@Badakaji Would you please update the task description with a screenshot of the cut-off headline?
From my testing on macOS and Windows 10 and IE11 with western script defaults it doesn't look like it's cut-off. The screenshot would help to let me understand and review/amend the patch better.

See here on my machine without your patch:

Would you please update the task description with a screenshot of the cut-off headline?

Fedora 38, Firefox 112, system font used is Lohit Marathi:

Change 908954 merged by jenkins-bot:

[mediawiki/core@master] Nepali text characters in section headings (H2) partially cut

https://gerrit.wikimedia.org/r/908954

Should this task be closed?

I'd want any Nepalese speaker, at minimum the task author @Badakaji to have a look at https://en.wikipedia.beta.wmflabs.org/wiki/Main_Page, amend the h2 with the script in quest from task description and also put lang="ne" on body or the heading itself in order to test if the fix is fully sufficient.

@Volker_E I have made the change here but I can't seem to find out how to change the language.

@Badakaji I've updated the headline accordingly on your sandbox.

Thank you @Volker_E, the heading issue seems to be fixed. It's ready for deployment in Nepali Wiki

Changes will show onwards when MediaWiki 1.41.0-wmf.9 is released to Nepali Wiki. Thanks @Volker_E for the help!

@Volker_E @Aklapper The H2 issue has been fixed but it has now effected the title; now the H1 cuts the letters.

I can confirm

Change 921553 had a related patch set uploaded (by Bada Kaji; author: Bada Kaji):

[mediawiki/core@master] Nepali text characters in section headings (H1) are partially cut

https://gerrit.wikimedia.org/r/921553

Change 921553 merged by jenkins-bot:

[mediawiki/core@master] mediawiki.skinning: Fix `h1` heading level 1 Nepali characters cut-off

https://gerrit.wikimedia.org/r/921553