Hi @k.menshov,
What you are seeing is a side-effect of the next-gen projects. To answer your first question and give you some more context regarding next-gen projects, you can read this post here from @mythili. Jira Cloud next-gen projects and Connect apps
The next-gen projects simplify the project configuration experience and allow non-jira-admins to create projects and configure them. All project configuration entities in these next-gen projects like issue types, statuses, and custom fields – are scoped to the project. Schemes don’t exist in these projects. Project configuration entities that are created within a next-gen project are only available to that project.
In terms of how to work with them, any issue type with a PROJECT scope are from next-gen projects and will always be scoped to that specific project, and these won’t show up on the main issue type page. Instead, these issue types will show up on the issue type page under the project settings of the project they are scoped to. The issue type that does not have a scope is the Global Issue Type that are used in Classic projects.
Hope that helps,
Edward Zhang
Senior Development Team Lead, Jira Platform