WordPress comments just vanished even tho there are about 250+ of them. Where did they go?

I manage a wordpress installation that handles quite a bit of traffic. We use WP-Cache and WP Thread Comment and recently, the owner noticed there was 250 comments on 1 post, but only one comment was showing. Here is a screenshot: http://cl.ly/3rtk

All the comments can be seen from the control panel of WP. But I think WP Thread Comment doesn’t have enough memory to pull all the comments so it just shows the latest one. Anyone have this issue?

Thanks in advance.

first thing I would do is to deactivate the Cache and see if that makes a difference. If disabling solves the problem, reset the cache for the comments of the particular post.

Probably something went wrong for the caching strategy and it ended up in some useless state.