WOPI - Excel documents do not switch to edit mode when clicking on "Edit in Browser" button

I have a WOPI service which returns in its CheckFileInfo all required data including:

"UserCanWrite": true, 
"EditModePostMessage": true, 
"UserCanNotWriteRelative": true, 
"HostEditUrl": "domain.com/Home/Detail/fileId?action=edit",
"HostViewUrl": "domain.com/Home/Detail/fileId?action=view"

However, when WOPI returns the Excel in View mode, clicking on "Edit in Browser" button does not switch the document into Edit Mode.

What could be the cause? Are we missing anything?

Below is the image of the edit button for Excel online

All of that was set. The issue was the official documentation which claimed that things should work out of the box after setting all of those properties in the CheckFileInfo response object.

Unfortunatly that was not the case. We had to implement the event listener for it to work accordingly.