So here is the basic situation. Today has had a lot of template changes here and there. In one particular case the styleid is being overridden by a plugin for various particular pages. Today, randomly, the entire page showed blank. I disabled vBO and the page worked, I enabled it and it died...
When the cron script is executed by a guest (or cronjob) it becomes guest cached. This can be fixed by adding the following to the init_startup plugin.
if (THIS_SCRIPT == 'cron')
$vbulletin->options['vbo_online'] = false;
3.8
ajax
bug
cache
caching
cron
different
disable
error
failed
fatal error
forum
full
full page caching
guest cache
html
image
modification
optimise
options
permissions
php
post
ten
timestamp
url
user
vboptimise
vbulletin
version