Some unicode symbols do not display correctly when copiousoutput is in effect

[dm1581 at gmail.com]

Hi all,

Some unicode symbols do not display correctly when a message in UTF-8
is displayed in the builtin pager or with a mailcap entry like
"text/plain; cat; copiousoutput".

If I remove "copiousoutput", the attachment naturally does not keep
open, but flicker for a fraction of a second, but I can see that the
symbols there are OK.

If I change the mailcap entry to "text/plain; less", the symbols
display correctly when the text/plain attachment is being viewed, and
are garbled in the pager.

If I set the default pager to, say, less, they display in the pager correctly.

The symbols themselves display correctly being pasted into the
terminal or if the email message is cat'ed to the terminal.

The different terminals (iTerm2 and macOS Terminal), the mutt
auto_view, assumed_charser, and charset settings as well as the LANG,
LC_CTYPE, LC_ALL env variables have all been played with to no avail.

Please advise as to how this issue can be debugged and solved.

Best,

--
Dmitry