When you say “pro version” you mean the plugin hosted here [1]? Because that plugin is not maintaining anymore, since July/2014. It was decided by our business team to migrate all its tools to the free version for easy deployment, centralized support, and facilitate the resolution of common/duplicated bugs. If you are still using that plugin, formerly named “Sucuri WP Plugin you have to uninstall that and install the free/community version named “Sucuri Scanner” which you can download from here [2].
If you keep seeing those errors with the styles using the new plugin then I would like to have a screenshot or some more information so I can check and resolve it, right now there is no much I can do with the information provided.
Let me know how do you want to proceed.
[1] https://wordpress.sucuri.net/
[2] https://www.ads-software.com/plugins/sucuri-scanner/
