User cannot access the right side panel for a locked document

Steps to reproduce:

1. Lock a document (edit a document with admin)
2. Go to the experience manager
3. Go to a channel that has the document from step 1
4. Go to that document
5. Edit content

Expected result:

The document should show that a document is locked by admin

Actual result:

The right side panel cannot be opened. The spinner goes forever.

Additional info:

The same bug is present if you schedule a document or request (de)publication. Or if you open the sidepanel for page that is not part of the current project (in progress).
Also, the breadcrumb changes to 'Content' in those cases at least.