Idea Summary
If you select a modal page as a target of a process redirect, when the page has the “Reload on submit” to “Always”, it just fails silently, without any warning and allowing you to select those pages in the branch pop up. This is absolutely confusing, as it fails silently without any apparenlty reason. This should ve avoided and detected as an error at the time of saving the page. This can be considered as a bug, because developers don't usually know or remember that apex behaviour.

Use Case
Avoid undetectable errors in apex development just for apex internal behaviours.

Preferred Solution (Optional)
Warn, or detect as an error the fact of selecting a modal page as a page process branch if the page is selected as “Reload on submit” as “Always”.