Opening a lead fails and throws error in log

[williamsdb]

Description

Since updating to the latest version last week some leads no longer open. Nothing appears to happen but the following messages appear in the log:

[2016-03-07 20:42:59] mautic.WARNING: PHP Warning: require(/var/www/mautic/app/cache/prod/doctrine/orm/Proxies/__CG__MauticFormBundleEntityForm.php): failed to open stream: No such file or directory - in file /var/www/mautic/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 207 [] []
[2016-03-07 20:42:59] mautic.ERROR: Fatal: require(): Failed opening required '/var/www/mautic/app/cache/prod/doctrine/orm/Proxies/__CG__MauticFormBundleEntityForm.php' (include_path='.:/usr/share/pear:/usr/share/php') - in file /var/www/mautic/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 207 [] []

Get very similar error on same line when I try to open the plugins config page too:

[2016-03-07 20:47:14] mautic.ERROR: Fatal: require(): Failed opening required '/var/www/mautic/app/cache/prod/doctrine/orm/Proxies/__CG__MauticPluginBundleEntityPlugin.php' (include_path='.:/usr/share/pear:/usr/share/php') - in file /var/www/mautic/vendor/doctrine/common/lib/Doctrine/Common/Proxy/AbstractProxyFactory.php - at line 207 [] []

Steps to reproduce

Try and open a lead - nothing happens

[williamsdb]

This turned out to be a caching issue and was resolved by deleting:

app/cache/prod

Maybe the upgrade process should clear this by default?