It's not only from the VisualEditor, but also from the talk page, proper editing page, and page history. There's also a similar problem with page information.

The logic should be that if a page is a redirect (which is quite easy to detect), then links to the tab should have &redirect=no appended to them.

I've realised that the problem with this is that the tabs use the links like

• https://en.wikipedia.org/wiki/Blancmange
• https://en.wikipedia.org/wiki/Talk:Blancmange

which cannot have &redirect=no appended to them.

Also, the code for this is in includes /skins.php

If you need proof:

https://en.wikipedia.org/wiki/Talk:Blancmange&redirect=no

You are talking about the different problem that was described in T5324: On redirect pages, "article" tab in top bar should lead to nonredirected page (&redirect=no). That problem is (almost) resolved and shouldn’t be an issue any more, unless you are viewing the redirect page itself. This is about VE-specific thing where it modifies URL incorrectly for redirects.