The Cloud Connect apps communicate through a special “app user” with the Jira, and this app user will be the member of the “atlassian-addons-admin”, “jira-users” and “jira-software-users” groups after installation by default. Due to this, the app user will have Application access in the instance.
Removing this special addon group, or modifying the default access groups is not recommended, and can casue well known issues with addons, eg.:
Make sure, that the default access groups are in place or if you change them to newly created ones, install the app after the changes, and grant Jira product access to these newly created groups.
Browse Users and Groups. Make sure that the Atlassian Add-On Administrator group (atlassian-addons-admin) has the Browse Users permission in the JIRA Global Permissions.
Administer Jira permission. Make sure that the group atlassian-addons-admin has the Administer JIRA permission in Global permissions.
Make sure that the "atlassian-addons-project-access" project role or the “atlassian-addons-admin” group has
'Browse Projects' permission under project permissions and
‘View Projects’ permission under project permissions and
'Edit Issues' under issue permissions and
‘Work On Issues’ under Time tracking Permissions (only recommended)
To be able to work on issues, make sure that the user has the “Work on Issues” permission in the project permission scheme.