texvc has not been generated for the 1.21wmf2 branch:

$ /bin/ls -1 /usr/local/apache/uncommon/1.21*/bin/texvc
/usr/local/apache/uncommon/1.21wmf1/bin/texvc
$

Fixed with:

dsh -F25 -cM -g mediawiki-installation -o -oSetupTimeout=10 'sudo -u mwdeploy /usr/bin/scap-recompile'

Also added to my deploy list

So apparently we no more recompile texvc when synchronizing the server. The script has been somehow abstracted out to scap-recompile which is not even puppetized.

Anyway, Sam Reed rebuild the texvc for 1.20wmf2 and that fixed the issue: https://test.wikipedia.org/wiki/Bug_41188

Sorry for the inconvenience.

Are we sure we got all the servers in the pool ? because there are reports from after the 18th about missing texvc binary

https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Failed_to_parse_.28Missing_texvc_executable.3B_please_see_math.2FREADME_to_configure..29

There are problems with the missing texvc on de.wikiversity and de.wikibooks, too:

https://de.wikiversity.org/wiki/Ganzer_Ringhomomorphismus/Basiswechsel/Aufgabe
http://de.wikibooks.org/wiki/Formelsammlung_Mathematik:_Identit%C3%A4ten:_Reihenidentit%C3%A4ten_nach_Ramanujan

And again at http://en.wikipedia.org/wiki/Socle_(mathematics) served by Served by srv285 if thats any help.

1.21wmf2 is no longer in use, so this is fixed (for now; bug 44653 describes similar issues with the 1.21wmf9 deployment). Bug 45076 has been filed for packaging texvc instead of manually compiling it on each server.