The PHP OPcache increases the performance of your shop by caching processed PHP source code in memory. The MageHosts servers are configured to re-read a script when it is changed.
However if you use a deploy method which switches to a new version of the code by replacing a symlink to a new release, PHP does not detect the change. This will cause strange things to happen.
If you use a deployment method which changes one ore more symlinks to point to the new version of the PHP code, you will need to flush the OPcache.
Execute these lines in SSH or in a script after the deploy to flush the OPcache:
echo '<?php opcache_reset(); clearstatcache(1); echo "OK";' > ~/httpdocs/flush_php.php
curl -L "https://$VHOSTDOMAIN/flush_php.php"