I have a user who reported this and following testing I have recreated it:
A list is deleted from a group connected SP Online team site by User 1 who has site owner permissions.
User 1 attempts to restore this list from the SP site recycle bin but cannot see the list.
When I view the site with site collection admin permissions I am able to see the list and restore it as normal.
Is it expected behaviour that User 1 would not be able to restore the list? I don't think it is, Site Owners should be able to view every file in the recycle bin.