Yep me too, it appears that the 4th element in the frappe.router.current_route from frappe.get_route() is an array, and not a string.
so…
this has an impact to reports_view.js on line 25 which sets the report_name.
which passes to the model to grab the report document
Which passes the array, so in the request the docname arg to frappe.desk.load.get_doc is an array.
@rohit_w can you look at please, you did the last merge to version-13.