fix

app/controllers/api/pm/issues_controller.rb

@@ -21,13 +21,13 @@ class Api::Pm::IssuesController < Api::Pm::BaseController
 
   def link_index
     pm_issue_type = params[:pm_issue_type] || [1, 2, 3]
+    not_join_id = @issue.pm_links.pluck(:be_linkable_id)
+    not_join_id << @issue.id
     object_issues = Issue.includes(:pm_links).where(
       pm_project_id: params[:pm_project_id],
       root_id: nil,
       pm_issue_type: pm_issue_type
-    ).where.not(
-      id: @issue.pm_links.pluck(:be_linkable_id)
-    )
+    ).where.not(id: not_join_id)
     @issues = kaminari_paginate(object_issues)
     render 'api/v1/issues/index'
   end