Try the code
HTML Code:
<a href="group.php?$session[sessionurl]groupid=$group[groupid]&do=manage" class="shade"><span class="underline">$vbphrase[members_pending_moderation]</span></a>: $group[moderatedmembers]
It's the code from 3.7 that would show the pending users. I'm not sure if it still works in 3.8 and have no board to test it

If it does still work then it's the conditional that's no longer valid.
The conditional that restricts the above code is
HTML Code:
<if condition="$show['pending_link']">
Exchange it for one that still works
HTML Code:
<if condition="is_member_of($bbuserinfo, 5,6,7)">
If it doesn't work than the code itself is no longer supported and its time to find another method :down: