macro trouble with tagged messages

[downtime]

So this worked on all tagged messages:

macro index,pager S '<save-message>=INBOX.Junk<enter>'

This works only on the currently highlighted message:

macro index,pager S '<pipe-message>bogofilter -Ns<enter>\
<save-message>=INBOX.Junk<enter>'

Why does the macro no longer work on all tagged messages when I add the
<pipe-message> macro command. And how can I check that the piped command is
doing its thing?

[downtime]

Reading the documentation, I found 'pipe_split'. The description of its function
sounded like it would fix my problem, but it didn't. Why would 'tag-prefix' stop
working with '<pipe-message>'?

Post by downtime
macro index,pager S '<save-message>=INBOX.Junk<enter>'
macro index,pager S '<pipe-message>bogofilter -Ns<enter>\
<save-message>=INBOX.Junk<enter>'
Why does the macro no longer work on all tagged messages when I add the
<pipe-message> macro command. And how can I check that the piped command is
doing its thing?