Scripts present in pages' content get rendered twice

Steps to reproduce

• Install the OpenGraph extension
• Create a page XWiki.Logger containing the following code:

{{velocity}}
#set ($logger = $services.logging.getLogger('debug'))
$logger.warn('Execution of script present in XWiki.Logger')
{{/velocity}}

• Visit page `XWiki.Logger`
• Inspect the log

Actual result

The log contains twice the debug log "Execution of script present in XWiki.Logger" on each page view, while the log should be present just once.