LTI tools can be restricted to a particular site (by site id), independently of being stealthed.
SAK-29136 introduced a regression where LTI tools that were site-restricted but not stealthed would appear available to add under Plugin Tools for any site. Adding such a tool will result in errors occurring in Site Info later on, as the site-restriction checks will fail if the current site is not allowed to use the tool.
To detect the presence of the bug, add an LTI tool that is restricted by site id, and not stealthed. Visit a site different than the one configured in the tool, and check Manage Tools. If the bug is present, the LTI tool will appear under Plugin Tools.