Comments Not Listed on Index Page, Incorrect display on post page

Here’s an odd comments problem.

My blog is at https://www.robhyndman.com. Around the time I upgraded to a 2.0RC a while ago (I’m now on 2.0), and just after I had someone create a new .htaccess file for me to redirect feeds to feedburner (the plug-in wouldn’t work for me), I noticed that the summary under post titles on my index page

eg: “#| 2005/12/29-10:10 pm | Law – Technology | Trackback | No Comments ?”

wouldn’t state the correct number of comments – always “No comments”, instead of the correct number.

And on the post page, ” No Responses to [post title]” but then all of the comments for that post.

The problem occurs for every theme. Oddly, some older posts don’t have the problem – the last post to do it correctly was Dec 17. Don’t know how that date is significant.

My .htaccess file reads:

RewriteEngine On
RewriteBase /

RewriteRule ^archives\.php /archives/ [R,L]
RewriteRule ^feed/rdf/ https://feeds.feedburner.com/Robhyndmancom [R,L]
RewriteRule ^feed/rss/ https://feeds.feedburner.com/Robhyndmancom [R,L]
RewriteRule ^feed/atom/ https://feeds.feedburner.com/Robhyndmancom [R,L]
RewriteRule ^feed/ https://feeds.feedburner.com/Robhyndmancom [R,L]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php
</IfModule>

# END WordPress

Any ideas?