Option :page: only works with a single page name not multiple

[SunbrightShinobi]

I made an example.drawio and using the syntax of :page: it or :page: uml it correctly displays that page. but if I :page: it,uml or :page: it uml i only get an empty box. Leaving out :page: option completely shows both pages as expected.

My Sphinx HTML output

My Sphinx Source and drawio file

My Sphinx environment