Composer update started resulting in: PHP Fatal error: Class 'Genemu\Bundle\FormBundle\GenemuFormBundle' not found

[RobMasters]

This fatal error has just started occurring for me today whenever I perform a composer update (i.e. when deploying using capifony). It is being caused by the following line in my Appkernel.php (which hasn't been changed in a long time) during the 'assets:install' command:

// in registerBundles array...
new Genemu\Bundle\FormBundle\GenemuFormBundle(),

Here is how I'm including the bundle from my composer.json:

"genemu/form-bundle": "2.1.x"

Has anything changed that could be causing this?

[RobMasters]

I'm not sure what the problem was but it seemed to work when I chose not to copy vendors from the previous deployment and update them, but to install them from scratch instead.