Problem with building poppler

[Dave Horsfall]

Sierra 10.12.6 (won't go any further), MacPorts 2.6.3 on a mid-2010 
MacBook Pro.

(Looks like "poppler" is part of "xpdf", my favourite PDF viewer.)

Whenever I do my regular "port upgrade outdated" I keep seeing the 
following, and it's starting to annoy me:

     --->  Configuring poppler
     Error: poppler cannot be built while another version of poppler is active.
     Error: Please forcibly deactivate the existing copy of poppler, e.g. by running:
     Error:
     Error:     sudo port -f deactivate poppler
     Error:
     Error: Then try again.
     Error: Failed to configure poppler: poppler is active

The "fix" is obvious of course, but before I file a bug report is this a 
known problem?  Error log available upon request.

Thanks.

(And yes, I know that I have a number of replies to acknowledge, but I've 
been busy/sick lately; comes from being in my late 60s.)

-- Dave