Error 500 by accessing "My Account"

[CSCSxx]

After upgrading ERPMine to 4.1.2 i got following error when i try to access to my Account:

Started GET "/my/account" for 127.0.0.1 at 2021-03-25 11:28:13 +0000 Processing by MyController#account as HTML Current user: technik (id=5) Rendering my/account.html.erb within layouts/base Rendered plugins/redmine_wktime/app/views/wkuser/_wk_user.html.erb (306.5ms) Rendered users/_mail_notifications.html.erb (42.7ms) Rendered users/_preferences.html.erb (70.4ms) Rendered plugins/redmine_wktime/app/views/wklead/_contact_info.html.erb (6.3ms) Rendered plugins/redmine_wktime/app/views/wkuser/_wk_user_address.html.erb (14.7ms) Rendered my/account.html.erb within layouts/base (464.5ms) Completed 500 Internal Server Error in 594ms (ActiveRecord: 319.9ms)

ActionView::Template::Error (undefined method `source_type' for #): 8:

9: <%= hidden_field_tag "attachment_ids", "" %> 10: <%= labelled_fields_for :erpmineuser, @user&.erpmineuser do |f| %> 11: <%= f.hidden_field "source_type" %> 12: <%= f.hidden_field "source_id" %> 13: <% end %> 14: <%= render partial: "wkdocument/attachment_form", locals: { container: @user, container_type: "Principal" } %>

plugins/redmine_wktime/app/views/wkuser/_wk_user_address.html.erb:11:in block in _d8ea15cac5a60ea4a6fb4fecb234144e' app/helpers/application_helper.rb:1365:inlabelled_fields_for' plugins/redmine_wktime/app/views/wkuser/_wk_user_address.html.erb:10:in _d8ea15cac5a60ea4a6fb4fecb234144e' lib/redmine/hook/view_listener.rb:61:inblock (2 levels) in render_on' lib/redmine/hook/view_listener.rb:59:in map' lib/redmine/hook/view_listener.rb:59:inblock in render_on' lib/redmine/hook.rb:63:in block (2 levels) in call_hook' lib/redmine/hook.rb:63:ineach' lib/redmine/hook.rb:63:in block in call_hook' lib/redmine/hook.rb:60:intap' lib/redmine/hook.rb:60:in call_hook' lib/redmine/hook.rb:98:incall_hook' app/views/my/account.html.erb:50:in block in _55c59bc7581967e4dc52c937e0d1f790' app/helpers/application_helper.rb:1358:inlabelled_form_for' app/views/my/account.html.erb:14:in _55c59bc7581967e4dc52c937e0d1f790' lib/redmine/sudo_mode.rb:65:insudo_mode' plugins/redmine_dmsf/lib/redmine_dmsf/webdav/custom_middleware.rb:60:in `call'

Environment: Redmine version 4.1.1.stable Ruby version 2.4.10-p364 (2020-03-31) [x86_64-linux-gnu] Rails version 5.2.4.2 Environment production Database adapter Mysql2 Mailer queue ActiveJob::QueueAdapters::AsyncAdapter Mailer delivery smtp SCM: Subversion 1.9.3 Mercurial 3.7.3 Cvs 1.12.13 Bazaar 2.7.0 Git 2.28.0 Filesystem
Redmine plugins: additionals 3.0.2-master mobile_issue_table 0.0.1 redmine_checklists 3.1.18 redmine_ckeditor 1.2.3 redmine_contacts 4.3.2 redmine_dmsf 2.4.5 redmine_issue_dynamic_edit 0.7.2 redmine_issue_todo_lists 1.3 redmine_issue_view_columns 1.0.1 redmine_lightbox2 0.5.1 redmine_logs 0.2.0 redmine_questions 1.0.2 redmine_wktime 4.2 redmine_xapian 2.0.3

[CSCSxx]

After upgrading Redmine Core to 4.1.2 it works again...don't know why...but..it works ;)