Michael Hudson-Doyle <michael.hudson@canonical.com> writes:

> I have encountered this too.  A C-u before entering the thread helps
> (this means already read messages are not rendered I think), as does a
> M-x notmuch-show-toggle-thread-indentation .  

Thanks, Michael.  This does help, though it makes it hard to interpret
context.  I'd love a solution that does not degrade utility so
drastically.