diff -r 0c14b3f23294 -r eed02e192770 mercurial/subrepo.py
--- a/mercurial/subrepo.py	Wed Feb 28 00:29:27 2018 -0500
+++ b/mercurial/subrepo.py	Thu Mar 01 11:13:00 2018 -0500
@@ -982,7 +982,13 @@
         if len(self._repo) == 0:
             # use self._repo.vfs instead of self.wvfs to remove .hg only
             self._repo.vfs.rmtree()
-            if parentrepo.shared():
+
+            # A remote subrepo could be shared if there is a local copy
+            # relative to the parent's share source.  But clone pooling doesn't
+            # assemble the repos in a tree, so that can't be consistently done.
+            # A simpler option is for the user to configure clone pooling, and
+            # work with that.
+            if parentrepo.shared() and hg.islocal(srcurl):
                 self.ui.status(_('sharing subrepo %s from %s\n')
                                % (subrelpath(self), srcurl))
                 shared = hg.share(self._repo._subparent.baseui,