LuCI index page gives error after login

Up-to-date OpenWrt master r21334-9b482ee22f & LuCI (7c3705b)

Login screen comes ok, but after login there is an error and no LuCI:

/usr/lib/lua/luci/ucodebridge.lua:23: /usr/lib/lua/luci/template.lua:158: Failed to load template 'admin_status/index'.
Error while parsing template '/usr/lib/lua/luci/view/admin_status/index.htm':
No such file or directory

Looking at the directory, there is luaindex.htm instead of index.htm

root@router1:~# ls /usr/lib/lua/luci/view/admin_status/
luaindex.htm

This should be a vanilla openssl based LuCI, bootstrap theme. (But also the openwrt-2020 theme is installed)

Full error shown:

Runtime error
Unhandled exception during request dispatching
/usr/lib/lua/luci/ucodebridge.lua:23: /usr/lib/lua/luci/template.lua:158: Failed to load template 'admin_status/index'.
Error while parsing template '/usr/lib/lua/luci/view/admin_status/index.htm':
No such file or directory

In error(), file [C]
  called from function [anonymous function] (/usr/lib/lua/luci/ucodebridge.lua:23)
  called from function  ((tail call))

In [anonymous function](), file /usr/share/ucode/luci/runtime.uc, line 138, byte 45:
  called from function [arrow function] (/usr/share/ucode/luci/dispatcher.uc:778:70)
  called from function render ([C])
  called from function render_action (/usr/share/ucode/luci/dispatcher.uc:768:24)
  called from function run_action (/usr/share/ucode/luci/dispatcher.uc:779:4)
  called from function [anonymous function] (/usr/share/ucode/luci/dispatcher.uc:993:48)
  called from anonymous function (/www/cgi-bin/luci:39:12)

 `        return lcall.call(modname, method, ...args);`
  Near here ----------------------------------------^