Serif and Monospace fonts scramble "st" letters combination

Attached illustration of the bug for both Serif and Monospace fonts (marked with red ellipses)

'retart' is not a typo! There is 's' letter, but not rendered by firefox.

My default encoding is "Central European".

I did not find the error in other desktop applications (tried yelp, openoffice, gedit) - 'st' is rendered fine there.
I also not found any other problematic combination of letters - only 'st'.

Problem occurs with "FreeSerif", "Serif", "FreeMono", "Monospace" fonts selected as default in Firefox.
It does not occur with "BitStream Vera Serif" font.

The problem did not exist in Ubuntu 5.10.

Some 'reportbug' generated info below:

Architecture: i386 (i686)
Shell: /bin/sh linked to /bin/bash
Kernel: Linux 2.6.15-19-k7
Locale: LANG=pl_PL.UTF-8, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8)

Versions of packages firefox depends on:
ii deb 2.15.2 Miscellaneous utilities specific t
ii fon 2.3.2-1.1ubuntu5 generic font configuration library
ii lib 1.11.3-0ubuntu1 The ATK accessibility toolkit
ii lib 2.3.6-0ubuntu14 GNU C Library: Shared libraries an
ii lib 1.0.4-0ubuntu1 The Cairo 2D vector graphics libra
ii lib 2.3.2-1.1ubuntu5 generic font configuration library
ii lib 2.1.10-1ubuntu1 FreeType 2 font engine, shared lib
ii lib 1:4.0.3-1ubuntu3 GCC support library
ii lib 2.10.1-0ubuntu2 The GLib library of C routines
ii lib 2.8.16-1ubuntu1 The GTK+ graphical user interface
ii lib 0.8.6-0ubuntu4 library for parsing CORBA IDL file
ii lib 6b-11 The Independent JPEG Group's JPEG
ii lib 2:1.firefox1.5.dfsg+1.5.0.1-1ubuntu9 Netscape Portable Runtime Library
ii lib 2:1.firefox1.5.dfsg+1.5.0.1-1ubuntu9 Network Security Service Libraries
ii lib 1.12.0-0ubuntu1 Layout and rendering of internatio
ii lib 1.2.8rel-5 PNG library - runtime
ii lib 4.0.3-1ubuntu3 The GNU Standard C++ Library v3
ii lib 2:1.0.0-0ubuntu4 X11 client-side library
ii lib 1.1.5.2-0ubuntu2 X cursor management library
ii lib 2:1.0.0-0ubuntu3 X11 miscellaneous extension librar
ii lib 1:3.0.1.2-0ubuntu2 X11 miscellaneous 'fixes' extensio
ii lib 2.1.8.2-0ubuntu2 FreeType-based font drawing librar
ii lib 2:1.0.0-0ubuntu2 X11 Input extension library
ii lib 2:1.0.1-0ubuntu2 X11 Xinerama extension library
ii lib 1:1.1.0.2-0ubuntu2 X11 RandR extension library
ii lib 1:0.9.0.2-0ubuntu2 X Rendering Extension client libra
ii lib 1:1.0.0-0ubuntu2 X11 toolkit intrinsics library
ii psm 22.1-1 Utilities that use the proc filesy
ii zli 1:1.2.3-6ubuntu4 compression library - runtime

Can you give a link to a page that shows the problem?

Here they are:
- monospace: https://wiki.ubuntu.com/RootSudo (Example#2)
- serif: for example http://www.gnome.org/ (set default font in Firefox Preferences to "FreeSerif" before entering page)

I also reproduced the error (with the same fonts) with ubuntu's Thunderbird - just click "Compose", set font to FreeSerif or FreeMono and type 'st'.

Still not reproducible in openoffice and other apps, the error seems to be gecko-specific.

I found a few bugs which look similar (especially the first one):
https://launchpad.net/distros/ubuntu/+source/firefox/+bug/31377
https://launchpad.net/distros/ubuntu/+source/firefox/+bug/36324
https://launchpad.net/distros/ubuntu/+source/firefox/+bug/23678

I just marked 31337 as duplicate of this bug as i found that only "st" combinations are broken too...

See 31337 for some screenshots too...

someone else than the poster confirmed it, so changing its status to confirmed.

looks ok with dapper preferred fonts (DejaVu), and Nimbus as well.

What were Breezy defaults? Were that 'FreeSerif'/'FreeMono' fonts?
If yes, then they can still have a problem after upgrade to Dapper, even if brand new installations won't see it...

The ligature was disabled in FreeFont SVN and is only optional now.
The version of FreeFonts shipped is buggy.

I can confirm this bug. The connection in between "st" occured with FreeSerif. The missing letter s in "st" occured with FreeMono. This happens when the fonts are used for the interface (application, windows, desktop...) and in programs (like Gedit). The bug doesn't occur in Openoffice.

Now when I type st, the letter s dissapears from the rendering, so it appears a misstype. I have seen this behaviour in meld and evolution mail writing component. As this can potentially induct rhe user to break data, I would suggest to elevate the importance of this issue.