Why is gnus not slurping *.in files

[Harry Putnam <reader@newsguy.com>]

I've used this code in gnus for a very long time:

(Bunched for mail)

(setq mail-sources
   '((file :path "/var/spool/mail/reader")
      (directory :path "/home/reader/spool/in/"    :suffix ".in")))

And gnus has faithfully slurped mail at /var/spool/mail/reader
And from ~/spool/<any mbox files ending in *.in>

I've moved operations to a new host and now when I tell gnus to scan
news/mail (C-g) those files are ignored silently.

Of course, I've checked to make sure those addresses are correct on
the new host, and they are.

How can I identify why the .gnus directive above is being silently
ignored?

One big thing that is different, is that I haven't yet moved my nnml
directories to the new operation.

But far as I remember when gnus slurps from the *.in files it creates
like named nnml directories as needed.

If it were a permissions problem somewhere surely gnus would issue
some kind of warning/error. But what I see in \*Messages\* seems to
indicate all is well:

[...]

Reading incoming mail from directory...
Reading incoming mail from file...
nnml: Reading incoming mail (no new mail)...done
Reading incoming mail from directory...
nnml: Reading incoming mail (no new mail)...done
Reading incoming mail from directory...
nnml: Reading incoming mail (no new mail)...done
Reading incoming mail from directory...
nnml: Reading incoming mail (no new mail)...done
Reading active file via nnml...done
Reading active file via nndraft...done
Checking new news...done

[...]

Looking in ~/spool/in/*.in I see the mbox files have not been
zero'ed out as they should have been, had they been read.

Further, no nnml directories have been created either, so seems
no reading is taking place... but silently as a ghost.