Per Thryduulf:

1. Load a redirect in visual editor (e.g. traplines)
2. Change the target of the redirect
3. Add a redirect categorisation template (in this case {{R from plural}}) to the body of the page

Results: VE placed the template before the redirect markup, breaking the redirect
Expectations: VE would place the template after the redirect, retaining it as a redirect

I have tested this and am able to reproduce, but I also find that adding a new line after the redirect, before adding the template, respects the given order and works as intended.