Solved. It was me! I was making links with pw-link -P ... but should have
used -L which I'm sure I tried, but must have failed for some other reason.
Quoting Wim Taymans (who's time I'm sad to have wasted):
"-L makes a lingering link, that is one that stays alive after pw-link
quits and is likely what you want. -P makes a link that is not activated
(for keeping things suspended) you probably don't want that."
--
John.