Velocity code shown when trying to translate some keys

e.g. here:
http://l10n.xwiki.org/xwiki/bin/view/Commons/xwiki-commons-extension-api?action=viewall&language=de
shows:

$escapetool.html($origtext).replace($util.newline, "
").replace("{{", "{{") 

for the "original text" of the key extension.log.applyaction.begin
The text triggering this error is:

Applying {} for extension [{}] on all namespaces