Delete a field in a content type breaks the site

Problem/Motivation

On a fresh Drupal Alpha 13 version I was not able to delete a field without breaking the website. I have try with different fields and I always get the same result.

Steps:

1. Install a fresh copy of Drupal Alpha13
2. Delete the comment type for the Article Content type
3. I will get a "No data received in Google Chrome"
4. If I reload I got a "The website has encountered an error. Please try again later."

Proposed resolution

I manage to get the site up and running again by dropping all the cache_* table.