[O] [OT] nobody (none)

[Roger Mason]

Hello,

An off topic problem.  I'm asking here because I noticed this problem
first in this list, but it has spread.

I read e-mail using gnus (v5.13) in emacs (25.3.1) on FreeBSD (10.3).
Some months ago I noticed some messages in this list displaying with
sender 'nobody' and subject '(none)' in gnus.  As the months have passed
the number of such messages has increased many-fold and spread to other
lists.  On opening the offending e-mail it is usual that the message has
both sender and subject fields with plausible contents.  Often, but not
exclusively, the 'nobody' messages originate from gmail accounts.

I have not changed any settings at my end so I assume some commonly used
component of the chain of email applications has changed settings and
that I need to respond to that change.  But where? and what?

Any hints on where to look would be most helpful.

Again, sorry for the OT message.

Roger