There are two instances of the text “Site Info” in the plugin, one in the local variable named “template_variables” inside function “sucuriscan_infosys_page” which technically speaking you can not access without extending the function.
The second instance of this text is in the global variable “sucuriscan_pages” used as a dictionary to build the sub-menu on the WordPress admin sidebar, this is the only thing that could be causing the issue. However, there is nothing in the code that could trigger a global replacement of text outside the scope of the plugin.
If you have not noticed, most if not all global variables defined in the Sucuri plugin are prefixed with the text “sucuriscan_” to avoid this situation of unwanted variable hierarchy, but this only works if the other plugins/extensions respect the same rules.
I suspect that your site has a 3rd-party extension or theme that is somehow extending this variable and using it elsewhere causing an unexpected behavior which in your case is translated to a replacement of the titles of the live pages of your site. Can you provide a list of plugins and themes installed in your site so I can try to replicate the issue in my own server?