Try deselecting/reselecting the Smart Group to tickle the item count into appearing (if it ever will; seems like certain criteria may inhibit it). It’s finicky and won’t always properly refresh, similar to the main window item count glitchiness. [edit: removed beta forum link]
Items counts are important to me so I hope problems with them will be fixed relatively quickly.
Still can’t get the item count to appear and still can’t control the Smart group itself. All files appear in the group even though I’m specifying only those over 2000KB.
Also I’m not “authorised” to view that link.